STATE UNIVERSITY CONSTRUCTION FUND 194 Washington Avenue. Albany. New York 12210

ERNEST L. BOYER CHAI RMAN T.N. HURD TRUSTEE

DARWIN R. WALES TRUSTEE OSCAR E. LANFORD GENERAL MANAGER

JAY R. HANDWERGER COUNSEL AND MANAGER OF FISCAL AFFAI RS "JOHN F. BUCKHOFF, JR., ASS ISTANT VICE CHANCELLOR FOR PLANT MANAGEMENT

JOHN FITZGERALD MANAGER OF DESIGN AND CONSTRUCTION MORTON C. GASSMAN MANAGER OF FACILITI ES PROGRAMMING AND PLANNING

"JOHN GROSVENOR ASSISTANT VICE CHANCELLOR FOR CAPITAL FINANCE AND ADMIN ISTRATION

JAMES J. McCUE DI RECTOR OF ADMINISTRATIVE SERVICES CHARLES M. SEGAL DI RECTOR OF PUBLIC INFORMATION ELWIN W. STEVENS MANAGER OF MARKETING AND RESEARCH

* Holding appointments in the State Un iversity's Office of Campus Development, which cooperates with the Fund in implementing the University's Capital Development Program.

An approach to the design of the

A LBERT G. H. DIETZ

Professor of Building Engineering

WI LLI AM M. C. LAM

William Lam Associates, Inc.

ROGER F. HALLENBECK

State University Construction Fund

A RESEARCH PROJECT

UNDERTAKEN BY

THE MASSACHUSETTS INSTITUTE OF T ECHNOLOGY

PROJECT ADMINISTRATOR

PRINC IPAL CONSULT ANT

SUC F

194 Wash ington Avenue, Albany, New York 12210, OCTOBER 1976

en C ! 5

CJ

Part I

1 2

Lighting design principles

Introduction 12

Perception of the visual environment 16

How we see 17

What we look at 20

What we see 22

How well we see 42

3 Visibility, comfort, and motivation vs . productivity 58

Visib ility and productiv ity 58

Motivation and product ivity 58

Comfort and productivi ty 59

4 Biological and activity needs 62

Biological needs for survival, sustenance & protection 63

Activity needs 75

Part II Lighting design practice

5 Programming an activity space 78

6 Lighting budget system 90

7 Lighting design process 98

Appendices

A Annotated bibliography 108

B Major results of Skidmore conference 124

C High points of London conference 130

o Reflectances for common building materials 132

E Some principles of good lighting 134

F Space Program Chart 137

-a .. j G) .. o

LL.

Application

The Lighting Research Project

This report is the culmination of on ~going research on the lighting

of bu i Id i ngs undertaken by the State Universi t y Construction Fund over several years. Th is research recogn ized that I ighti ng levels

cou ld be reduced in buildings without affecting performance, thus

anticipating the need to conserve energy by severa l years.

The material in this report is presented as a service and for the in­

formation of all those concerned with the Luminous Environment.

Part I speaks to Ligh t ing design principles and Part I I is concerned wi t h Ligh t ing design practice. The intent is to ident ify and docu~

ment an approach which makes the lighting design process trans~

parent so that inherent trade~offs may be clear ly recognized and

dealt wi t h. The application of the material in this report is not mandatory on State University Construction Fund projects. Many

designers and others concerned wi th the luminous envi ronment may find this material presents a different perspective or indeed

reinfo rces thei r th inking on the pr inciples and practice of light ing design.

Ear ly in 1966, the New Y ork State University Const ruction Fund comm issioned the Schoo l of Architectu re at Pratt Inst itute to re~

view l ight ing research produced du ri ng the past f ifty years, and to

evaluate light ing recommendati ons stemm ing from it. The study

showed that most research had been concerned with establishing illumination levels for careful ly defined and restricted tasks under controlled conditions. Furthermore, these levels frequently had been incorporated uncritically into lighting codes for use in design projects where the actual environments differed widely from the research environments. The study concluded that criteria estab­lished from past research requires revaluation in terms of a general approach to lighting design.

As a result of this preliminary investigation, the Fund decided to undertake a project which would have the following objectives o to reconcile field observations with research findings,

o to study the importance of environmental factors in the design process, and

o to establish a design approach which would be meaningful to specialist and non-specialist alike.

To implement the project, the Fund commissioned the Massachu­setts Institute of Technology to conduct the research. Dr. Albert G. H. Dietz, Professor of Building Engineering, was selected as head of the project group; Mr. William M. C. Lam of William Lam Associates, Inc., Cambridge, Massachusetts, was chosen as princi ­pal consultant to M IT. The SUCF coordinator at the project's in­ception was Mr . Richard G. Jacques, Director of Research and Development.

The first major event of the project was a two-day conference on

"The Luminous Environment", held at Skidmore College, Saratoga Springs, New York, in July of 1967. In bringing together outstand­ing representat ives from the behavioral sciences, medicine, educa­tion, architecture, and illumination, the objective of the confer­ence was to obtain spec ific suggestions for a performance approach that would be of value to SUCF and also be adaptable to general use. An ou tli ne of the major accomplishments of the conference and a complete roster of the participants are given in Appendix B.

From the Skidmore Conference came many constructive results, notably, the overall emphasis placed on the humanistic elements of perception, such as proper rendition of co lor; acquisition of meaningful information; avoidance of discomfort, distraction, and gloom; and the creation of a comfortable and pleas ing visual envi­ronment. Both special ists and general ists agreed that many prob­lems in lighting design cannot be overcome by the simple appl ica­tion of numbers f rom a chart. The designer and architect often face situations which are not clear-cut, and therefore many deci­sions must be based upon personal value judgments. It was hel d that, for any approach to be of value, guidelines must be offered upon which judgments may be f irmly based. The participants agreed that the remaining work of the project should be directed toward establ ish ing those gu idel ines.

The first tangible result of the Skidmore Conference was an in­terim report prepared by the MIT group. Published in April of 1968, it described the direction the research was to take, explained

Format

the coverage and format for the final report, and solicited com­ments and suggestions.

After reactions of readers were obtained and evaluated, in June a second two-day conference was held, this time in London . At this meeting, attended only by key participants concerned with spe­cifics of the final project report, its scope and content were formu­lated and agreed upon. Highlights, as well as the roster of partici ­pants, are given in Appendix C.

The intent of this report initially drafted in 1970, is to present guidelines, rather than restrictive codes, for all those persons invol­ved in the design and evaluation of an environment that is illumin­ated : the users, administrators, planners and designers of the spaces.

Th is report is divided into two parts: Part I Design principles, and Part II Design practice. Although the two parts are separate enti ­ties, Part I should be considered as general background and explana­tory material, introducing the concepts which are elaborated upon and applied in Part II. Those who choose to follow the approach presented in this report will find that after becoming familiar with the principles presented in Part I, further use will be necessary for occasional reference only . They may wish to use the more tech­nical data and charts in Part lion a more regular basis . Taken to­gether, the two parts emphasize guidance and education, and con­tain a summation of what is believed to be a useful direction for design of optimum I ighting conditions.

"Until the end of the nineteenth century, the quality of light in buildings was

restricted because the area of -glazing was limited by structural requ:rements

and artificial light was expensive. Since th en, however, technical developments

have made it easy to provide increased quantities of light, whether daylight

through curta in wa lling or electric light from fluorescent tubes. As a result,

new buildings tend to be saturated w ith light, and the skill in its use (which

was once dictated by scarcity) has been lost."

"During the last ten to fifteen years the ex uberance of the quantitative ap­

proach has come to be tempered by an increasing interest in the ways in which

the expert deployment of lighting can genuinely en hance a building. But these

new ideas and techniques have not yet been integrated with the general prac­

tice of 'illuminating engineering'. Th e time has come to take stock of the situa­

tion and set down the basis for a new approach." 1

The problem at the Houston Astrodome (shown in Figu res 1 and 2) is an example of a situation that can result when performance cri­

teria are based on the most easilv measured factors, without a broader recognition of what people look at, how they see, how

well they see, or what they see as the physical attributes of the ob­jects they are viewing. The glass orig inally provided in the dome

gave adequate light (quantitat ive ly) but the players were unable to dist inguish the ball against the pattern of structure.

The types of problems encountered at the Astrodome, can be

avoided by applying a performance approach based on a common sense philosophy:

o the objective must be positive, create a desirable environment, rather than design for tolerance levels.

o the emphasis must be on achieving the best environment, rather than on satisfying minimum requirements.

These goals can best be achieved through an appreciation of the

basic principles of perception and an understanding of the infor­mational/psychological aspects of the luminous environment.

Part I of this report takes an intensive look at the complexity of

perception, based on a review of research and literature in this and related f ields. The technical terminology frequently used to des­

cr ibe the luminous environment has been replaced, whenever pos­

sible, with everyday language. Because it is drawn from everyday

life and employs common usage terms, this language can be quick­ly understood by the generalist as well as the specialist and can be

uti l ized in questionna ires and user surveys without requiring trans­lation . Some technical terms that cou ld not be translated, or com­

mon words which have a slightly different meaning in this context, are defined in the Glossary which follows.

1 Jay. Peter. "Seeing Light", The Arch itects Journal. I nformation Library, 4 January 67 _ SfBAb 7: UOC 628,9001.

Figure 1 } 2. Conflicting patterns of l ight and dark ma ke it impossible to see the bal l in Astrodome roof; solution: to pa int the glass areas

-

> ... as U) U) 0 -~

Affective

Attributive

Brightness

Brilliant

Constancies

Emotional aspects associated with an object or situation .

FactuallY descriptive aspects used to describe an object or scene.

Brilliance of light perceived. A quali­tative measure of light as opposed to luminance which is a quantitative measurement of light energy.

Implies a strong, unusual, or sparkling brightness, often changeful or varied; and often too strong to be agreeable.

Elements that tend to be perceived consistently, regardless of context.

Dark The perceived quality of having little or no light. Implies a more or less com­plete absence of light by comparison.

Dazzle

Dim

Disability Glare

Foot Lambert

Glare

Luminance

Luminous

Luminous Ceiling

Mirror Angle

To overpower or reduce the vision by intense light. To confuse vision by ex­cess light.

Perceived as not being bright .

Glare which creates conditions in which a person cannot function safely or effectively.

Unit of brightness; equal to the bright­ness of a surface which is radiating or reflecting one lumen per square foot.

An interference with perception caused by a bright light, i.e. visual noise.

The quantitative measure of bright-ness of a light source or an illuminated surface, equal to luminous f lux per unit projected area of its surface:

Luminance (ft-L) ; Illumination (1 m/ft2)

X Reflectance

Radiating or reflecting light.

Transi ll uminated ceiling of back lighted translucent material.

An angle of reflectance where the angle of incidence equals the angle reflection; in reference to the viewer, an angle equal and opposite to the viewing angle.

Normal Angle

Perceive

Perception

Phototropic

Satisfy

See

Simultaneous Contrast

Sensation

Solid Angle

Sparkle

Specular

Visual Noise

An angle (or plane) which is perpen­dicular to another surface.

To obtain knowledge through the senses; to apprehend with the mind; to understand.

The meaningful impression of any ob­ject obtained by use of the senses; awareness of objects; consciousness; direct acquaintance with anything through the senses. See SENSATION for further clarification.

Referring to a change in which light is the orienting stimulus.

To fulfill the desires, expectations, needs, or demands of. I n general, to satisfy is to meet to the full one's wants and expectations; to content is to give enough to keep one from find­ing fault or complaining.

To perceive with the eyes; to perceive things mentally; to construct a mental image of.

A situation created when some objects seem brighter than others of equal luminance in a uniformly illuminated space.

That mode of mental functioning which stimulates the bodily organism, including seeing, hearing, smelling, etc. Specifically, the direct result of the present stimulation of the sense organs, as distinguished from perception which involves the combination of different sensations and the utilization of past experience and context in recognizing the objects and facts from which the present stimulus arises.

The angle formed by three or more planes meeting at a point, as at the apex of a cone.

An attractive brilliance.

Having the property of a mirror.

An interference with perception from unwanted stimuli.

A "good" environment helps us do what we wan t t o do and feel the way we want to feel doing it. Our senses make us aware of the visual, aural, thermal, tactile, and olfactory aspects of the environ­ment. For an awareness of a "good" envi ronment, we require each of these aspects to contr ibute in an appropriate com bination w ith the others. For example, in a baseball stadium we want to be physi­cal ly stimulated and cheer our team; in a restaurant we want to re­lax wh il e eating and conversing w ith compan ions.

The things we do are divided into activities and sub-act ivities. I n a restaurant, these might be:

activities: eating and drinking, conversing and relax ing. sub-act ivit ies : reading the menu and ordering the meal, per­ceiving food and imp lements, selecting, chewing, swallowi ng, peop le-watching, and gaz ing out the window.

Each act ivity and sub-activity has characteristics of: importance frequency sequence location participants

These character istics provide us w ith a quantitative framework with which to compare the var ious act ivit ies (including feelings) we exper ience with in a given environment, and are hence a basis for design criter ia and performance evaluation.

For each activity and sub-activity there are optimum environmen­tal conditions under which we would like to operate. If several dif­ferent activities must occur w ithin a given space, compromise is in­volved since the opt imum condition for one act ivi ty is unlikely to be the optimum for any other. The cons ideration of act ivi t ies and sub-activities in terms of their importance, frequency, sequence, location, and participant characteristics is necessary for intelli­gent programming, design and eva luation. The spatial requirements can be sat isfied withi n a framework of the var ious enviornmenta l disciplines (visua l, thermal, acoustic, etc.), each contributing in an "appropriate" combi nation with the others.

VISUAL ENV IRONMENT

How we see

Figure 3

Expectation - Whether the view or the figure ascend ing the stairs is seen depends on the vie'NE!r's information needs.

17

The unl imited number of stimuli constantly bombard ing all of a person's sensors are substantial ly more than he can ass imilate at anyone time. Through the perception process he therefore selects and interprets on ly those st imu li that will assist him in perform ing particular act ivities.

A visua l "stimulus" is an object (let's call it a signal) that is visible to the perceiver. Stimuli fall into three categories: o a central stimulus is a signal relevant to satisfying a need. o a peripheral stimulus is a less important signal, unconsciously

selected to help understand the central signa l or to satisfy an alternate need.

o an irrelevant, disturbing, or unwanted st imulus is called noise.

Because stimul i are constant ly changing, the environment is re­corded , not as a passive picture-taking process, but as the result of active selection and interpretation of informat ion needed for ac­t ivities and basic biological functions. If Mr. Gray, for example, is looking for a friend, the person si lhouetted in Figure 3 wi ll be his object of focus. On the other hand, if Mr. Gray is just concerned about walking down the stairs, his eye will seek objects of orienta­t ion: the railing, the landing, the view through the window, the people in the distance, and the weather condit ions.

Since perception involves selection and interpretation, the process logically starts with a need, but this need is seldom satisfied through only one of man's senses. Consider the example of a student in a building looking for the office of the registrar What visua l informat ion must the stu dent seek to help fulfill his need? He will need information that signs can give him, and he will need to know when other people are present in order to avoid co l lisions or perhaps to ask directions.

Through his "experience fi lter," the student's visua l selector will direct his eye movements to locate the relevant stimuli in his visual world. This f ilter includes:

stored information: personal past experience in this particular building, or generally w ith offices, corridors, or building sur­face materials. stable characteristics: prejudices, interests, methodical or assumptive decision-making. current state: rushed or at leisure, happy or depressed, friendly or quarrelsome, sick or well, and present occupation.

The brain, through what we will call a "visual selector," dictates the scanning pattern of t he eye. This is active scanning to gather part icu lar information to satisfy a biological need (f irst and fore­most) or an activ ity need. Th us, routine contro l of eye movements

HOWWE SEE

18

by the brain is sometimes overpowered by seemingly involuntary movement of the eye toward a stimulus wh ich may be a potential

threat or danger to the body.

In the case of the student seeking the registrar's office, his selection of stimuli is influenced by his needs and experience and by the visual world in which he finds himself (including the stimuli and their context). If he were a senior class officer and familiar with the building, he would need very little visual information to get to the registrar's office. In contrast, a freshman, in the building for the first time, depressed with the confusion of h is first registra­tion, would need all the visual information available to get to the office. The freshman will notice people, color or walls, and much seemingly extraneous information the senior probably does not notice. The freshman's basic need for orientation will thus over­power his conscious activity need. Eventually, the orientation need w ill be satisfied, and the student will perhaps notice a protruding sign, or direct his attention to clues in the environment (perhaps directional arrows in the corridor!. and find what he hopes will be the registrar's office.

As the student approaches the general location of the office, the selection process directs his eyes to doors, rather than to people, colors or shapes. Once the eye focuses on a door, the visual input. as well as input from the other senses, must be interpreted. The student will more easily "see" the registrar's office if he hears the sound of typewriters and registration instruct ions being given to another student.

Interpretation of inputs is accomplished through the experience

filter discussed earlier and what we wi ll call a "processing selector." It is as a result of the processing selector that informa'tion of less immediacy is stored as past information without a person's being consciously aware that the transfer has occurred (the information may be "recalled" later) . More immediate or relevant information for satisfying a need is used at the point where the perception is formed.

Each bit of information is always related to its context in this pro­cess. As a result, when the input information becomes a perception, it has attributive, affective, and expectant characteristics. This means that the student finds an office, likes the efficien t way in which it appears to be run, and expects to be able to register there. If indeed this is the registrar's office, he wi ll already have other needs involving the perception process: locating the person to help him, presenting approved class schedules, and so on. If this is not the registrar's office, the student's origina l activity need will not be satisfied, and he must travel through the process again, with the same needs, but with an addit ion to the stored information in his experience fi Iter.

Figure 4

The process of perception

w a; .... w

'" .... r-- .... -' <n

.... ~ 2

w a; w a; U :0 2 U w

" 2 a;

'" <n w U Q.

i= X !!? w a; w .... U

'" a;

'" :I: U w -' ., Ol

'" .... <n

2 0 i=

'" :;; a; 0 ~

~

" w a; 0 .... <n

HOWWE SEE

To help simplify the complex function of perception, the entire

process is summarized graphically in Figure 4. This chart is to be

read from the top down with the upper part of the diagram repre­senting The Visual World, at the bottom is The Brain including "the

experience filter", with The Eye, the visual sensor of the viewer

connecting the two. The flow lines indicate the routes various vis­ual signals take in order to satisfy a biological or activity need. These needs are discussed in more detail in Chapter 4.

·· jl

PERCEPTION: I .

ATTRIBUTIVE AFFECTIVE

EXPECTANT ~ PRESENT NEED

= RESPONSE

SENSORY P=~============~ INFORMATION

. NEED

r----~.II'-----"-----o

VISUAL

~=========i INFORMATION SELECTOR

~======== INFORMATION r SELECTOR

UNCONSCIOUS

l========~ PROCESSING SELECTOR

PERCEPTION: ATTRIBUTIVE

l========~ AFFECTIVE EXPECTANT = RESPONSE

.. II

II

Jl

NEW NEED

19

VISUAL INPUT

INPUT FROM OTHER SENSORS

.

VISUAL ENVIRONMENT

What we look at

20

I n the previous section, the perception of the environment in re­lation to our needs was discussed. The eye searches for clues­signals that supply various bits of information for activity and biological needs. In this search irrelevant signals or noise are re­jected and we look at what we want to see, even if it is not as at­tracting phototropically as something else in our visual field. For instance, if we are looking for a friend, the landscape in Figure 3 would be a background to the silhouetted figure. But we would look at the background because (1) information found there helps satisfy our biological needs for orientation, physical security, and contact with nature, (2) we always see an object in the context of its background, and (3) its higher luminance interferes with per­ception of the person.

Involuntary eye movements, or distractions, occur as the result of unexpected changes in the peripheral field. These changes can be

in relation to: o size: an unusually large man passes by.

o motion: a person unexpectedly enters the room.

o brightness: a specular reflection or dark shadow is seen.

o color: a green spot is detected in the cake we are about to eat.

We examine the changes to see if they are of sufficient biological or functional importance to call for redirection of our attention. Distraction of biological importance may be due to danger, an un­desirable situation, or an ambiguity.

o if specular reflection or an unusual dark shadow suggests danger, we look for other visual clues to clarify the situation. We may even shift attention from the visual to our other sen­ses: we may sniff the air, listen for unusual sounds, reach to feel familiar objects, or instinctively move out of the path of suspected danger.

o An example of an undesirable distraction of biological impor­tance is a dirty windshield which interferes with information necessary for safe driving.

o Ambiguity often distracts us for longer periods of time. Win­dows as sources of light can be somewhat ambiguous if there is nothing recognizable that can be observed through them. Windows are more comfortable to look at and less distracting if familiar elements are visible (trees, buildings) or if some physical object is visible just outside the glazing plane (win­dow reveal, roof overhang). The most ambiguous window is one that has wh ite translucent glass since it appears first to be a uniformly overcast sky.

WHAT WE LOOK AT

Figure 5 Perception of st ructure distorted by uneven lighting

21

When distraction is functionally important we may redi rect our at­tention because new information suggests that we change our pres­ent course. For example, while hammering a nail we notice that the board is too short, cracked, or discolored; we will not continue hammering if we are concerned about our finished product.

Occasionally, a source of d istraction is close to our intended focus and overwhelming in luminance or strength of pattern.

When distraction is by domi nance of luminance, there is a reduc­tion in t he visibility of our object of attention, because of the ten­dency of the eye to adapt to high luminance in self protection, e.g. when we are dr iving towards the sun. An example of dominance by strength of pattern was the roof of the Houston Astrodome be­fore it was painted, where the more powerful visual pattern (visual noise) prevented the players from fo llowing th e ball.

Despite its high brightness, we have no need to constantly make reference to the sun because it is natural for it to be there, and we have evidence of its presence by other means (such as the high­l ights and shadows it causes). On the other hand, w ith a bright

light source that is ambiguous, unnatural, or unwanted, we will re­turn to invest igate and find it annoy ing. I n the same way, unexpect­ed distortion in percept ion of the structure in Figure 5 commands as much attention as the view of daylight which has much higher lum inance.

In summary, we look at what we want to see (not necessarily the brightest object in view)' unless something more important is in­dicated by the environment. When the things which are illuminated do not relate to our needs, we will be distracted - not necessarily by too much lum inance, but by disturbing information.

What we see

•••••• I -. • • • • • •• • •••••• Figure 6 Most memorable form or classifiC<Jtion

Figure 7 Figure background conflict

Figure 8a Figure/background conflict

VISUAL ENV IRONMENT

22

A closer look at the perception process Because perception consists of the complex processing described in the previous sections, what we see (that is, how things look to us)

cannot be described as a simple relationship between stimulus and perception. We perceive each object or grouping of objects as hav­

ing attributive (inherent and factual), affective (emotional and

psychological), and expectant (assumed) properties. Examples are

given in the follow ing paragraphs.

I n an attempt to make life simpler for ourselves, we always seek to

understand what we look at by classifying it in to the most recog­nizable form or classification. We see a circle, rather than 15 dots

in Figure 6.

We always select a signal (shape) from a context (background), un­

less there is a perceptual ambiguity; in this case, we shift back and forth, at some expense in effort and discomfort. What is selected

as a signal is determined initia lly by need or by what is under­

standable. When looking at black and white stripes of uniform

width in Figure 7, we find it difficult to make a choice between

background and foreground.

After Hesse lgren. The language of Architecture. 1969

The same difficulty is present with a different configuration .

Compare looking at the central portion of Figure 8 as opposed to

the top or bottom edges.

WHAT WE SEE

Figure 8b Figure/back ground conflict from uniform width of stripes is reduced when o ne set is more meaningful than the other - the view rather than the blind slats.

F igure 9

Figure/background conf lict

Figure 10 Complete perceptions -Rub in's figure ( faces! vase)

23

When looking through venet ian blinds, figure/background conf li ct f rom uniform w idth of stripes is reduced because one set of st ripes is more meaningful than the other - the view being of more in­

terest than the blind slat .

We f ind that the conf lict between the figure and the background is greater when the shapes are simi lar to the background spaces. Note the "dazzle" effect in Figure 9(b). When black and white areas are equal, arrangement is relevant.

•••••• •••••• •••••• •••••• •••••• ••••••

• U

a. Background shapes different from fjgure b. Background shapes similar to f jgure

We exper ience complete perceptions; we do not see separate at­tributes of shape, size, color , or brightness, e.g. we see a man, a ball, etc. For instance, when we look at the objects in Figure 10, we exper ience complete perceptions; we can see faces silhouetted against a w hite background or a vase against a black background . Each perception is who le and we find it impossible to see both faces and vase at the same time. We do not perceive a ser ies of curves and lines and then laboriously add these up to create meaningful combi nations, unless we are trying to analyze our perception.

WHAT WE SEE

a. Ret inal image of table setting

Figure 11 Stable visual world

24

In the same way, we see objects with their attributes in a contex t and in relation to use, feel, odor, and so forth-except in the isolat­ed laboratory situat ion where context and meaning are taken away from objects for experimental or explanatory purposes. In real life, individual components such as size, brightness, shape, or color can­not be related to simple measurement of only one dimension or a multi-dimensioned stimulus. Our visual system is not a group of gauges capable of measuring luminance, visual size or co lor.

We perceive a stable visual world. We see th i ngs as we k now them to be, not as they appear momentari Iy. When we move ou reyes and head, the two-dimensional images may change, but we perceive the unchanging room as it is. (Look around and see if your table moves.) We wil l almost never actual ly see a round image, but the elliptical shape wi l l generally be seen as "round." We may identify a p late because of its "roundness," or we may assume it is round because we expect a plate to be round, as shown in Figure 11.

b. Perceived form of the same sett ing

Perception components Because of our tendency to see a stable world, we can refer to con­stancies of size, shape, color and brightness when we discuss com­ponents of perception.

Every perception has each component discussed in the following tex 1. All the components can be used t o describe any object . Some naturally take precedence, and anyone can be st ronger than the others. The breakdown of individual components is artificial; in actua li ty, attributive, affective, and expectant aspects are contin­uously interacting and influencing one another. The attributive (factua l ly descriptive) aspects of percept ion relate only sl ightly to

strength, size and color of the momentary stimu lus. The immediate

image of the stimulus (in compari son to what the object is) is a re­

sult of constancies, expectati on, and the relevance of the percep­tion to current needs. On the other hand, the affective (feeling) as­pect of perception comes from the relationsh ip between the at-

WHAT WE SEE

F igure 12 Context expectations -- size constancy

a. Plate on large table

25

tribu tive properties of the object and its expected appearance When the lum inance levels, gradients, patterns, colors, etc. are re le­vant and expected, positive affective descr iptions follow; the saille properti es without relevance wi ll resu lt in negative affective descrip­tions.

Attributive aspects: size constancy Percept ion of size is influenced pred ominan tl y by context rather than by optical size. Withou t a context, we cannot tell if we are look ing at a small ob ject from a short distance or a large object from a long distance. The size of one object is judged in relation to

b. Same plate on Slnall table

all other objects in the context. A plate will seem smaller on a large table than on a small tab le; an open-ended I ine will seem longer than a closed one as illustrated in Figure 12.

A tr ick room can foo l us. Are the women in Figu re 13 really of a di f ferent size? We can expect a certa in relationship to exist with cei ling height, furniture size, et c. The three cy li nders in Figu re 14 are geometrically equa l in size. We expect the en tire scene to have the same perspect ive.

Hes:selgren. l-:--'e Language of Architecture, 1969, (After 1ttelson)

-." i

1

A Figure 13 Expectation -- defined room ratios

Figure 14

Expectation - - same perspective over ent ire scene

WHAT WE SEE

Figure 15 ExpecWtiofi - - depends on the swndard" which face? or whtlt kind of ball7

Fiqure 16 Context expecta tion s - diswnce

F i ~Jure 17 Con tex t expectat ions - shape cons t;)ncy

26

Is the object to the right in Figure 15 a ping-pong bailor a beach ball? It depends upon whether it is related to the nearest face o r the face farthest away. Also, if we know the kind of ba ll, we ex­pect a certain relationship and wi ll be able to tell how far away each face is.

Aher Hessef9ren, The Language of An:I1' tecture , 1969

As we judge size by distance clues, so we judge distance by know­ing the size of the ob ject; or we may judge relative distance by compari ng overlaying objects in the background as in Figure 16.

We can judge movement only by comparison . We feel more move­ment on foot than at 700 miles per hour in an airplane. In a tra in station we sometimes have difficulty telling if it is our train, or t he train on the next track, that is moving.

Attributive aspects: shape constancy Figures are seen in the context of other objects and based on a com­mon perspective: a table when viewed from across the room is seen as a rectangle, even though optically it takes the shape of a trape­zoid . This characteri st ic of retaining a perceived property (or shape) despite varying stimulus dimensions is called shape constancy. Shape is also affected by expectation. In the street scene in Figure 17, expectat ion makes us "see the street curve beyond the corner."

WHAT WE SEE

Figu re 18 Contex t expectati ons - co lor constancy: simultaneous con trast

Figure 19 Context expectat ions - color constancy: simultaneous contrast with a connect ing clue

27

Attributive aspects: color constancy This att ribute permits us to see a plate as it is over a wide range of

normal lighting condi tions, even though color photographs of these

condit ions may be ve ry different. By observing the plate in context

with other objects at the same tab le, we can tel l if it is a white plate illuminated by a red bulb, or a red plate illuminated by a white

bu lb. As long as al l objects have the same il lumination, only mini­

mal c lues are necessary . For instance, in a comp letely black labora­

tory background when the only ob ject visib le is a red disk , one can­

not make the di st inct ion just cited . But the presence of one white thread across the disk wi l l make the distinction clea r, and allow us

to separate the characte ri stics of the p late f rom those of the ill um­

ination2

Color constancy can be upset by certain lighting and background

cond itions, however . The plate wi ll appear to be of a darker shade

when viewed aga inst a ligh t-colored tablecloth, as opposed to ·a

darker one. This occurs because of simultaneous contrast, as shown in Figure 18.

But co lor constancy w ill prevai l if there is only one connecting

clue as demonstrated in F iqure 19. After Hesselgren, The language of Architocture. 1969. (Aftel'" 8alinkinl

Because of color constancy, ou r friends' appearance will seem

natural over a wide range of w hite lighting condit ions. We wi ll not

not ice that they look different outdoors in the sun, shade, or un­

der an overcast sky, or indoors under fluorescent and incandescent lighting, even th ough the camera would make these distinctions.

If, however, illumination color changes greatly (say from whi te to

yellow), we w ill not ice that our friends and o ther objects are be­ing "tinted" by a colored light. Such tinting mayor may not be

disturbing, depending on our expectat ions. I t is not disturbing, for

instance, in a discotheque or at the theatre.

2 Hurvich, Leo M. and Jameson, Dorothea, The Perception of Brightness and Darkness, A llyn and Bacon, Inc .• Boston 1966. p. 86 "Gelb Effect."

WHAT WE SEE

Figure 20 Expcclat ion - sunlight Clnd shadow· natural and pleasant

In Figure 20, expectation makes the lighting natural and pleasant, rather than uneven and gloomy. The pavement is perceived as a continuous material in sunlight and in shadow.

B~cuase of expectation (der ived from past experience) one ex­pects illumination to be of a high color temperature when lumin­ance levels are high (reference to daylight) and low co lor tempera­ture when luminance levels are low (association w ith fi religh t, candleligh t, etc .). Kruithof has measured the range of co lor tem­peratures under which objects appear "natural" and pleasant.

Figure 21 Color temperature reference chart (data from Kruithofl ~Qo+--f-----+---+----+--f---i

From Lighl. Col u' ,1Ild Environmem by FJber 8irron c 1969 by Lill un EduCd 1r o "al Pul)loshi'IQ. Inc. AOPfinled b y pe rmissio n of V ,ln Noslr,,1lCl Reinhold Cumpany.

28

'""+--f-- --+---+-- - -+--i---1 I~O . _ _+-- -_j- - _j- --+-+--_i ,,+--f----+---+----+--i---1 '"+--'-- --+----+-----+---+---1 ,,+--f----- +---+----+--f---i

WHAT WE SEE

Figure 22 Expectation - comparison

29

The v iew through a bronze or gray heat-reducing glass window usual ly is not distu rbing because the viewer does not "compare" the view. However, the color of the glass wil l be noticed and w ill be disturbing if an open or clear window is also in his field of vis­

ion as in Figure 22. When there is a basis for comparison, the view through such glass appears tinted and "gloomy ."

Accurate judgement of co lor needs fu l l spectrum light such as heated "black body" sources, e.g. incandescent light, sunl ight. In order for two objects to match in perceived color under a wide range of illumination, the two objects must conta in proportionate amounts of all the same colors. To ensure this universal match the ill uminant must include the entire spectrum, w ithout any f re­quency bands omitted or accentuated. Such accurate color judge­ment is necessary for matching paints, for example.

Memory and past experience also playa large role in perception. One way in which color memory maintains a constancy is through the "spot effect.',3 If we are walking in the woods, a brilliant shaft of sunlight through the leaves will produce a spot on the ground which may at first appear to be a scrap of white paper . But upon

3 lbid., p. 86 and 87, "Shadow and Spot Effects."

a. Woodland scene from a distance

Figure 23 Perception - memory and past experience

30

b. Whi te spot becomes leaf

closer examination, we discover that the spot is a sun li t leaf as il­lustrated in Figure 23. Henceforth on that walk, we always see a sunlit leaf and not a spot of "white."

Another way to test color memory is to look at a sheet of paper on

your desk and then out the window at a sheet of the same color on

the daylighted street. You w ill see the two sheets as having the

same co lor even though the ex terior illumination may be 1000 times greater than the inter ior illumination . You wil l have allowed

for the different context.

Attributive aspects: brightness constancy Just as we separate size from distance when judging size, so we

separate object color from illumination color when judging bright­ness. This is called brightness constancy. Luminance is the techni­

cal term for measured brightness, just as angular size is the techni­

cal term for measured size. We do not see lum inance per se,· it is a

description of a specific condition which, to the observer, is in­f luenced by expectation . .

Each person's visual system is able to detect a property of "bright­ness" over a very large range of luminance produced - from sun­

light to moonlight (one million to onel . Abi lity to perceive lum in-

WHAT WE SEE

Figure 24 c. Shape versus direction of light

31

ance differences in adjacent patches is call ed contrast sensitivity, and is described mathematica lly in the next section of this chapter ("How wel l we see") . Assessment of brightness between objects that are not adjacent, however, involves the whole perception pro­cess. If, in a labora tory, a disk is illuminated at va ri ous levels, a doub l ing of luminance woul d produce a "just noti cable d ifference." Thus, an increase of four times the luminance would produce two "just noticabl e differences" -- not very much. But, in ou r daily experience, many other factors come into playas the eye adapts to each luminous scene: contex t, experience , and expecta­tion are taken in to consideration when perceiving w hether an ob­ject is dark, l ight, too brigh t, or dull. For instance, an in teri or space may seem "brighter" than a daylight scene even though the ex teri­or lumi nance is 1,000 t imes greater. Consider these perceptions:

o a bright cafeteria vs. a bright cockta il lounge. o sunlight on a window sil l vs. light f ix tu res of equa l luminance. o a bright mural vs. a dirty dish cart.

When the mental observat ions are compared w ith ligh t meter read­ings the results may be surprising I

Another point to consider about luminance is that we " see" a sur­face as cont inuous and evenly ligh ted as long as the luminance gradient seems natural for that shape. And in situations where there may be no evidence of the direction of the light sou rce, we most commonly understand the shape of three-dimensional oblects

Reprinted by permission from The Architect$' JourtliJi

w hen we can assume ligh t direction from above. In a laboratory setting, we are somet imes confused if ligh t comes from below, as

in Figure 24b.

When the source is obvious there is no confusion, as in Figure 24c; we compensate and adapt automatica ll y. In fact, if· we were to wear goggles that invert all images (gl asses that " turn the wor ld up­side down") we wou ld very soon adapt to the situa ti on and see the world righ tside up.

When we view ob jects il lumi nated by d ifferent light sources, we are not conf used if the sources are obvious, blending of ligh t is gradual, or the illumination is of different surfaces, e.g. an incan-

Figure 25

Color of light by comparison

Figure 26

Expectation versus uniform ity of light

32

descent source on the carpet and a fluorescent source on the wall.

At nigh t , one does not notice the color of the handrail light in Figure 25a; but during the day, it seems yel low in compar ison with daylight from the skyl ight above, as in Figure 25b.

A flat, uniform surface is expected to appear that way . T herefore,

non-uniform luminance is much more noticeable in a flat cei ling than one with coffers (Figure 26) where shape is defined by grad­ients.

Another concern is the rate of change of luminance. A ceiling ap­

pears to be evenly lighted, flat and of the same color when the luminance rate of change is constant, even though the luminance

at the window may be 20 times that at the inner wal l.

A change of rate implies a change of shape, and the difference in

WHAT WE SEE

\ \

a. Continuity of surface

Figure 27 Luminance - rate of change

Figure 28 Luminance - rate of change: scal lops

33

Reprinted by permission from The Architects' Journal ,

b. Surface interrupted

lum inance would be noticeable if the shape is obviously constant (refer to Figure 26). Also, if the continuity of the surface is def­initely interrupted by a beam or stripe, the two areas may appear of differing color but evenly illuminated, even though the lumin­

ance gradient is otherwise constant.

This same phenomenon can be utilized, for instance, by having a color change, or prominent joint line, in a concealed lighting cove where a brigh tness rate change is unavoidable (as in Figure 66b) . If "scallops" of light are centered between columns or reveals, the changing rate of gradient becomes less noticeable. In addition, "scallops" seem natural to the perception of panels when they are al igned in a modular fashion, but tend to fractionalize the uniform wall in Figure 28b.

WHAT WE SEE

Figure 29

Adap ta ti on level and apparent brightness . I n any given scene, the ey e sens itivi ty se ttles down to a general average state of adap ta ti o n. Th is <lc ts as a ' reference standard' such that ind ividu<l l items o f the sce ne wh ich have a higher physictl i lurninance than this re ference level ' look bri gh t ' , and th ose with a low er luminolnce 'l ook dark '. T he bri ll i-C1 nce o f th e hiDhlights and th e murk iness of the shad ows consequently depends no t o nly on their intr insic phys-iCol lumin(Jnc(! , bu t a lso on the state of adaptation to the eye. Raise the addp ta ti on and the shiJd ows look darker. Lower the ad [J p Wt ion (sc reen the w indow w ith y ou r hand) ,mu the shadovvs look brigh ter. So do the h igh ligh ts. T hus in thed i<.i9ralTl i.l surf uce w i th a lum inance of 100 ft- L has <In dPlhl rcnt br igh tness of 100 when o ne's eye is adiJpted to 100 fl-L, bu t the S<.1 m e surface wou ld have an apparent briqh tness of 230 when one's eye was adapted to 10 ft- L.

from Hopkinson, R.G. and Kay . JD , The L igh ting o f p y ' k BU ild ings, Freder ick A. raeqer , New a , 1969, and

Fober oDd Felber , London: 1969 .

F igure 30 Simu ltaneous con trast - dark room, w i th on ly disp layed IJb jel:\S iltu rni niltcd

The dominat ing feat ure of human vision is adaptation. Everything

we see is referred to some reference level- w hether of l igh tness, darkness, or color-and we make ou r in terp reta ti on in terms of t h is adapt ing reference level. All visual exper ience has some basis in

: :>,

220 ~r. -- Jo-, 100 "L. .-' -

lc-

~ ..!'.: J --,_ e-

"" t;:; 10 z " ., " e

~ -0: oJ , "

j I -......

r----1 0 . 01 0 . 1 10 100 1000

MAPTAT!()"l LVr11lJA:lCE FT-L

past or present knowledge.

Br ightness, as we ll as color, is affected by simultaneous contrast. Only di splayed objects are il luminated in the photograph in Figure 30. These objects seem brighter than those of equal luminance in a uniformly illuminated room.

,

Figure 3 1 Simultaneous contrast - light room, only display area

ill uminated

Figure 32 Simu ltaneous contrast - lighl room and cei ling, display objects illuminated from luminous ceiling (objects appear dark in comparison with ceiling)

I llumination of the Rembrandt paint ing in Figure 31 is kep t low for reasons of preservation, yet it appears much brighter than the paintings in Figu re 32 which receive ten times more light from a luminous ceiling. (The Rembrandt would seem even brighter if the surrounding walls were dark or unlit.)

WHAT WE SEE

•••••••••••••••••• •••••••••••••••••• ••••••••••• 0 ••••••

•••••••••••••••••• Figure 33 Luminance - pattern: simple and regu lar

Figure 34 Luminance - pattern: simple. regular, and large scale

36

When the light source is directly visible, or when reflected on a polished surf ace, pattern becomes a more important aspect than usual. For example, expectation makes burnt-out lamps very

noticeable in a ce iling where the pattern is simple and regular as in Figure 33. This is espec ial ly true if the pattern elements are large scale and visually strong, as Figure 34 shows.

The strong pattern plus the confusing reflection in Figure 35 re­sults in increased distraction, thus raising the level of visual noise already inherent in that type of lighting system.

WHAT WE SEE

Figure 35 Luminance - pattern: visua l noise and distraction

37

Affective aspects In addition to the attributive (factually descriptive) aspects just

discussed, there are affective (emotional) aspects associated with

our perceptions of an object or scene. Some of the terms we will use to describe those feelings and their physical correlates are:

FOCUS

DISTRACTION

GLARE

SPARKLE, GLITTER

GLOOM

DULL

DRAMAT IC

INTERESTING

DISORDER

INT IMACY

When large, bright colorful or moving objects are the intended objects of attention, a positive focus exists. If those objects

are not intended to be the focus, they can be a distraction in

either of two ways.

WHAT WE SEE

38

o a pleasant diversion when alternate needs are satisfied, e.g. a

beautiful girl passing by, a pleasant view from a w indow.

o an unpleasant diversion when the information is irrelevant, unwanted (bright light fixtures, highlighted wastebaskets) or

ambiguous (translucent windows, patterns, or colors which

upset constancies or expectations).

An object can be sparkling instead of glaring if it is the desired ob­

ject of perception, e.g. a chandelier, a view, or a patch of sunlight. Hence relevance or irrelevance of the scene, rather than brightness

ratios, determine "glare."

Gloom is experienced in the following situat ions:

o There are difficult conditions for performing an activity, e.g.

not enough I ight; focal object obscured by shadows; or the focal object silhouetted rather than highlighted.

o Desired biological facts are 1) difficult to obtain: observer ex­

cluded from view, sunshine, or feeling of daytime; 2) unclear:

upsetting constancies such as size, shape, color or brightness; no focal points, visual rest centers, sparkle, or interest; and 3)

dominated by unwanted facts: dominance by overly bright ceilings or bright overcast sky; dominance by objects outside

the immediate area where privacy is desired.

If we select the ground objects in Figure 36 as the desired objects

to view, we find them dark in comparison with the overcast sky .

(A!so, the overcast day may seem "dark," even though luminance levels may be hundreds of t imes greater than a "bright" interior

space.) On a sunny day, when shadows define and emphasize their three-dimensional aspects, the ground objects will appear brighter than the sky. At night, we consider a street "brightly illuminated,"

although the sky is always dark. This is shown in Figure 37.

A subject of great interest is seldom described as dull. Something inherent ly dull visually cannot be made less dull by greater lumin­

ance. It must be changed and given interest by the addition of

colors (such as paint in a parking garage), shadows, or the dramatic upsetting of constancies (such as pools of light along paths of cir­

culation). A scene may appear dull because the intended object of

attention is dominated by something dull. In tent ional upsetting of constancies can create "drama," excitement, or tension. If this up· setting of constancies not appear to tie in tentional, the same effects can be gloomy and disturbing.

The angled buildings in Figure 36 do not seem disorderly because

t he contextual background of sky and woods are direction less. The

"office landscape" in Figure 38 appears disorderly in the context

of a highly directional geometric background.

WHAT WE SEE

" " , ..

w " " "

Figure 36

Expectation - order and frame of reference

Figure 37 Expectat ion - br ightness

39

a. Strongly directional ceil­ing with coordinated furniture arrangement

Figure 38 Expectalion - order and frame of reference

WHAT WE SEE

40

An intimate feeling (meaning private, closely personal or cozy, but not necessarily dark) can be achieved in a dining room for example

by separate pools of I ight, by separate booths, or by effective use of plant materials used as a screening device.

Expectant aspects The expectant aspect of any perception governs the next action of

the observer. Expectations also influence the attributive (factually descriptive) and affective (emotional) aspects of the visual exper­ience.

Two immediate expectations relative to perception are security and insecurity. Turning the lights off in your living room does not

create tension. Yet tension is felt when the lights go out unexpect­

edly in an urban park because unkown and unexplained causes create apprehension and fear of danger. The dominant perception

is that there may be possible danger in this "dark" park (an ex­

pectant aspect) with resulting behavior leading to the focusing on

possible danger sources or a means of escape (such as a park exit).

When no danger is expected, a similar moonlit park in exurbia may not be perceived as being "dark."

b. A strongly directional ceiling combined with offi ce landscaping pro­duces "disorder"

WHAT WE SEE

4 1

What we see: summary An understanding of the process of perception and the compon­ents of percept ion help to explain why a room interior may ap­pear "too bright" at nigh t , but "too dark" during the day because of memory of simultaneous exterior conditions. This effect would be increased if there were a black w indow at night and even just a crack of day l ight dur ing t he day for reference.

Our judgment is altered by what we expect to be bri ght in a given environment under given conditions for a part icu lar activity . An unlit mu ral, located as an obvious focal po int in a room, would ap­pear dark because we expect that it was meant to be featured . A chandelier in a theatre always appears too bright if even barely l it during t he performance, t hough not too bright at ful l intensity during t he intermi ssion. Highlighting an empty f ireplace or an ug ly f loor would create a scene described as "too bright" except to the jan itor as he is sweepi ng up. Th is means that, to produce a predic­table brightness perception level, those involved in design must determine what shou ld be perceived, as well as the dimensions of the st imuli (lumi nance).

VISU A L ENVIRONMENT

How well we see The f ollow ing general relationship can be used to develop an under­standing of how wel l we see

How well we see = Accuracy + Ease of forming defined perception

Avai lable information

Accuracy, Ease of Perception, and I nformation are critical para­meters, dependent upon the character istics of the object perceived, the con tex 1. and the state of the observer, as well as upon the source of illumination. However, since we are accustomed to think of visua l capaci ty in terms of strength of stimu Ius, we shall discuss that parameter first.

Visual capacity vs. strength of stimulus The effect of the strength of the stimulus must be considered both in term s of sharpness of vision (acuity and object size) and con­trast sensitivity (contrast within and/or between objects and back­ground). As indicated on the graph in Figure 39, as the background luminance increases, visibility initially increases also up to a point.

BASIC VISIIl I LlTY : 3PlGo nt iESS RE QU I REMENTS

'lACKGROU ID BRIGHTNESS

t ~

< -" ? ~ ~

100

" 80

" " so

" lO

20

10

---.; ~

~~~

~-- ...

(F('OTL/.'~RTS ) ,01 .05 .,

- - - - -- ---------- ----, -'i$:~ ';.. ---" <ft s?~-. ~,,\\-s

Q \'>-- ...... o~ \f<. ",\~~~,,\1.~

\-\;/ ~--~ '\~~O ~ \ \-\1' ~ ... "f'i)

. , " " '00 1000 10 , 000

VISIBlLlTY : EQUIVALENT ) I Llll"ll ' IATI(J1 REQl.llREM':'IHS ( FOOTCA' IOLfS • LIGHT TASK .~:------~c----'----~------~------~~------~------~

( so' REFLEC TNlCE ) . Ol 25

(lARK TAS K ( S' REFLEC TA',ICE ) .1 25

Figure 39 Vi sibility chart

.115 .

I. 25

42

I .-25 • • . . 12 . 5 '" 1250 12,500 . . .

12 , 5 '" 1250 12,500 125 , 000

But both curves reach a point of diminishing return above which large increases in background luminance produce only a smal l in ­crease in v isibility.

Our visual acuity is at 57% of maximum at 1 foot-Lambert (ft- L), 78% at 10 ft- L. When background brightness is raised f rom 10 to 20 ft-L, visual acuity is increased by 3%; by on ly 1% when the in­crease is from 50 to 60 ft-L; and by a miniscule 0. 1% when the increase is from 100 to 110 ft-L. Therefore, for v iewing small ob­jects (when visual acuity is the limitation), a minor increase in size

HOW WELL WE SEE

Figure 40 Visual acu ity - watchmaker's magnify ing glass

43

(with optical aids, when possible, such as a magnifying mirror or

watchmaker's eyepiece) is worth more than an infinite increase in quantity of illumination (F igure 40).

When a chalkboard is to be viewed, a decreased viewing distance of

25% is equa l to one hundred times (1 Ole to 1000 fc) the amount of light. When visual acuity is the limitation, the implication is for

the teacher to write larger and for the handicapped to sit in the

front of the room. However , visibility is more typically limited by lack of cont rast f rom a number of causes ca talogued in the

f ollowi ng sections.

For contrast sensitivity, a relationship similar to that for visual

acuity exists. If it is necessary to detect fine differences in contrast, high levels are required. However, when it is possible to control contrast, it is more econom ical to increase contrast rather than il­

lumination. For exam ple, sof ter pencils or a better off ice duplicat­ing process are better alternatives than increasing illumination

several fold.

Illumination can vary greatly the amount of contrast and, there­

fore, the required contrast sensit ivity. For instance, only one foot­

candle is necessary to i l luminate a chipped grain of wood if the

light is placed so as to graze the subject at an ang le; tor the same

object, a diffused light may require 1000 footcandles.

Clarity of object characteristics The clar ity of object characterist ics relative to defined informa­

tional needs has a great influence on how well we see at various

luminance levels. The amount of information available is a function

of size and contrast of details of the signal. If we assume size is fixed , is the information from the con trast relevant to what we

want to know? The amount of contrast produced in an object is

dependent on object characteristics (in addition to quantity). If we

are in terested in color, it is dependent on the light spectrum of the

source; itwe are interested in texture, it is dependent on di rect ion and how concent rated or d iffused the il lumina t ion.

It is not only necessa ry for t he eye to detect contrast , but also to

interpret the meaning of the contrast accurately. What the contrast tells us is impor tant. What information do we want about the object? For instance, high contras t between reflection of the ligh t

source (shine) on the object, rather than other characteristics, would not be of value. Multipl e internal shadows contuse the shape

of some objects. If we are interested in color proper ties, sha rply

cast shadows w ill compete for attention.

A summary listing of some typical information needs, object characteristics, and relevant illumination characteristics is shown

in Table I , inc luded at the end of this chapter. Examples of two

Figure 41 Luminance - position

Figure 42 Adaptation

HOW WE LL WE SEE

44

and three dimensional number/letter designators of object charac­teristics (with wh ich objects will be classified from this point on)

follow Table I and Table II.

The clarity of an object also may be reinforced or reduced by con­text. One aspect of context is information value. Understanding of the shape of wire sculpture (305)* could be increased by shadow from a single light source, or could be confused by multiple sha­dows·- especially if location of the sources is not obvious and the sculpture is complex . Other aspects of context are phototropic effect, simultaneous contrast, and color. Context, for example, may produce positive or negative information for the 'observer and may hel p or reduce object perception by means of shadows cast or distracting form. (The experience at the Houston Astrodome il­lustrates the negative effect : the pattern of the structure over­powered the visibi l ity of the ball.)

Examples of a sol id object related to other su rfaces by a cast sha­dow (303) are given in Figure 41. Shape and defined edges of the

shadow can be important in determining the position of the object

(the ball) if there are no other references .

Clarity, of course, is improved through adaptation. A large bright source is adapted to in one of two ways as illustrated in Figure 42:

o by making the signal appear darker than the bright background.

o by causing stray light in the eye, thereby reducing visibility.

How well something is seen depends first on looking at the object: focus. A competing signal gets the observer's attention and is either a distraction (a negative attraction, such as the Houston Astrodome cei ling) or an emphasis (creating focus, a positive attraction such as underlining text) . Distraction or emphasis occurs when the compet­ing signal is:

o more powerfu I, o of stronger pattern, o more meaningful. o implying danger, or o perceptually confusing.

The effect of distraction/emphasis considerations on design and hardware decisions is discussed in the sect ion on loca l lighting.

*$ee Table II

HOW WELL WE SEE

Figure 43 Local lighting with light source baffled

Figure 44 local lighting positioned for maximum effectiveness

45

The observer's attention The observer's attention is influenced by many factors. The pre­vious discussion on focus/distract ion is relevant here. The more the distraction, the harder it is for the observer to keep focusing on the signal; the more the focus, the less effort the observer extends to the signa l. The motivation and mood of the perceiver determine the length of attention span, as well as willingness to concentrate and fol low through with activities. Visual rest centers provide re­lief from focus; people have limited attention spans and need some interrupt ion in concentration to maximize vigilance, and counter­act boredom. If the rest center is in the distance, shifting to it uses different eye muscles and reduces fat igue.

Experience With experience, the observer needs fewer clues from which to form a meaningful perception. Objects are seen more accurately with less information by experienced observers because they know what to look for. For example, someone who has never hunted can find animals in the woods on ly with great difficulty, whatever the v isual conditions; a trained hunter, on the other hand, takes advantage of all relevant signals. Experience in perception is partic­ularly relevant in testing situations, where untrained observers should not be used except in specia l circumstances.

Maximum focus and minimum distraction are produced by local lighting (with the light source baffled) The signal on ly is illumin­

ated to maximum brightness and the context is of minimal distrac­tion, as shown in Figure 43.

Local lighting can be posit ior1ed for maximum effectiveness with­out introducing "glare" or intense heat for persons in the room. For instance, local lighting can be piped through an acrylic rod during assembly of electron tubes, as illustrated in Figure 44.

HOW WELL WE SEE

Figure 45 Local lighting plus magnification

Figu re 46 l oca l lighting - background competi ti on

46

Local l ight ing w ith magnification is more effect ive than an infinite amount of general illumination without magnification, as in Figure 45.

When the competing background is of higher luminance than the signal, the cla rity of the signal is reduced. The effect is greatest when the background (as the source of adaptation) is located closest to, or surrounds, the signa l. When there is a glossy tab le top, as in Figure 46, background competition can be reduced by locating sources ou t side the mirror angle.

Figure 47a Mirror angle demonstrated

Figure 47b Clarity of object characteristics - 2D2 - totally gloSSY objects (photographs) and background, with appropriate lighting

47

The following pages contain a series of photographs illustrating the clarity of object characteristics in various contexts and at va r ious luminance leve ls, as well as the importance of geometry (size, shape and positionl rather than quantity.

Light source at the mirror angle is shown in Figure 47a. Figure 47b shows a tota ll y glossy object and background (2D2 on Table III . The illumination is modest; the position of the source is pro­per, relat ive to specular su rfaces (away from mirror angle, as shown in d iagram l. I llumi nation of v iewer and of opposite wa l l are negat ive factors (mi rror reflectionsl . Excessive frame shadows are avoided (deep fra mes not used, light not grazingl.

HOWWELL WE SEE

Figure 48 Clarity of object characteristics - 203 and 3011 - totally glossy with no inherent color

48

When the ref lected image is used positively, the exact pattern is important. The four photographs in Figure 48 illustrate two char­acteristics: totally glossy object w ith no color on dark background (2D3). and totally glossy object with no inherent color (3D1 1)

HOWWELL WE SEE

Figure 49

Clarity of object characteristics - 202 and 306 - totally glossy with inherent color and solid seen in silhouette against glossy background

Figure 50

Clarity of object characteristics - 207 - dark matte on

glossy background: specular ref lection

49

Figure 49 illustrates characteristics 202 and 306: totally glossy with inherent color (202): swimmer under water with a reflected image of a window on the surface of the water . This situation prevents observation of the swimmer under water unless the bot­tom of the pool receives illumination from directions other than the mirror angle (multilateral daylight or artificial supplementary underwater lighting). Reflection of direct sunlight on water can be almost impossible to counteract, even for viewing swimmers on the surface of the water.

A solid seen in silhouette against a glossy background also illus­trates 306: benefits are obtained from a uniform source at the mirror angle in the amount of contrast of the swimmer against water . If the coach would like illumination from other directions in order to see details of a swimmer's motions, contrast between swimmer and water must be reduced.

Suhstantial artificial illumination is required to counteract window reflections in the situation where there is a low window on one side of the room and the other walls are of dark wood finishes .

A scratch on a polished metal plate, shown in Figure 50, is most effectively illum inated from a grazing angle. If light is directed away f rom the mi rror angle, the indentations are highlighted and the background becomes a darker mirror. Greatest contrast and visib i lity are produced by a un iform source at t he mirror angle, thus allowing the scratch to appear dark aga inst the bright re­flection as in Figure 50.

HOIVWELL WE SEE

Figure 51 Clarity of object characterist ics - 208 - metallic glossy against dark matt: increased illumination at the mirror angle maximizes visibi lity

50

Polished metallic surfaces (and mirrors) can only ga in luminance trom a mirror angle. At night polished meta l bu il dings present the same prob lem. Flat polished metal letters against a dark back­ground are brighter than the background during the day (when reflecting t he sky), but cannot be illuminated from below at night. Convex or concave letters present a mirror angle between sources and viewers at many angles.

a. Book in normal position

The ser ies of photographs in Figure 51 illustrate the difficulty of illumi nating book titl es properly. Probably the most diff icult book t it les to read are t hose printed in si lver or go ld (208 and 209) Vi sibility of dark glossy titles is maximized by the oppos ite meth­ods f rom those used for maximizing contrast of silver and gold titles.

Visib ility is maximized (increasing the inherent contrast) by in­creasing illuminat ion at the mirror angle (the type) relative to that at other angles (the bindings).

b. Book tilted UJ1

Tilting the book up maximizes the amount of illuminated surface al the mirror angle, bul because of the rounded sp ine, on ly hall of the prinling is enhanced .

HOW WELL WE SEE

Figure 52

Clarity of object characteristics

A 307 - Dark raised object

Shadows cast by dark letters on Spacing the letters from the a light colored background background tends to reduce always reduce clarity. the negative effect.

51

Tilting the book down greatly reduces the amount of illumination at non-mirror angles (the binding), but contrast is increased be­cause the binding becomes darker than the printing. The same effect is achieved by shielding the binding with one's hand.

c. Book tilted down

Either of these steps is more effective than increasing the illumina­tion level substant ially without chang ing the geometry . Correct lighting geometry is much more critical than t he illumination level. A larger source area in the mirror angle, such as an indirectly illuminated ceiling, maximizes the contrast.

The clarity of raised objects, such as letters, is particularly affected by object/background values. Shadow from a dark raised letter (307) on a light-colored background always reduces clarity: spac­ing the shadow from the background reduces the negative effect. Dark letters are better flat or recessed where shadows either do not exist or fall within the letters. On the other hand, shadows are helpful when light-colored letters are raised; when light letters are recessed, they lose contrast by shadows. Figure 52 illustrates these conditions.

30B - Light raised object

Shadows are helpfu I in perception of light raised letters.

A Light letters, when recessed, lose contrast when partially filled by shadows.

HOW WEL L WE SEE

a. Backlighting

Figure 53 Clarity of object characteristics - 2Dl0and 3013-transparent

b. Backlighting plus magnification

52

Transparent objects (2D10 and 3D13, as in Figure 53) are best seen by back lighting. In the laboratory, titrations are often better undertaken against the background of a well-illuminated white wall rather than by direct lighting on the equipment itself. Cer­tain technical inspections, such as those on television picture tube screens, require backlighting and magnification rather than an in­crease in direct illumination.

HOW WE LL WE SEE

53

Perception of a closed sol id object with detail (302) can best be understood by considering the problems involved in the perception

of faces. Clarity of object characteristics requires that certain in­formation needs and hardware systems be met:

information needs: clarity of perception requires visibility of details and color as well as total form. hardware systems: illumination should have a dominant direc­tion (vector) neither coinciding w ith view ing direction (which produces minimum modelling) nor perpendicular to viewing di rection (which produces maximum modelling); shading and shadows should not be excessively dense nor confusing. Dense shadows from the side are better than those from above or below because faces are more symmetrical on the vertical axis. In addition our "seeing" normally includes aggregate information from constan tly chang ing horizontal directions, but with a fixed vertical direction. When the direction of the lighting on an object is poor, the ratio of maximum to mini ­mum illum ination should be low, particularly for viewi ng faces . The optimum ratio would be less than 10 to 1, ideally between 2 to 1 and 5 to 1. If the direction is good, of course, the ratio can be higher than 10 to 1. Such ratios and clar ity are attainable from a single concent rated source combined wi th diffused sources (wh ich can be reflected l ight from wa lls, floors, table tops, etc.) or from non-uniform d iffused sources (dominant from one direction such as a w indow, rather than a perfectl y uniform hemisphere such as a totally enveloping overcast sky) . Multiple point sources can prod uce the proper ratios, but are likely to be accompanied by multiple shadows. For faces illuminated with low maximum/minimum ratio, direction is not so cr itical; w ith a high maximum/m inimum ratio, side direction is much better than overhead.

How well we see: summary In this section we determined that quantity of light is only one of the many factors in determining how well we see. Each viewer has specific information needs and each object has specific character­istics. Relevant lighting geometry, rather than quanti ty, is the most effective way to meet these needs and characteristics. Visibility is also relative to focus, distraction, and context. Above very mini ­mum illumination levels, the geometry of light source and objects viewed is far more important than light quantity. To increase visibility by brute strength (footcandles) rather than skill (geomet­ry) is wasteful and likely to produce bad side effects in the form of glare.

HOW WE LL WE SEE

Visual information needs, object surface characteristics,

and illumination qualities

most likely to reveal and obscure the needed information

Table I

Maximum surface brightness

Totall y matte surface (201 . carpet)

Il lumination normal to the surface. The surface shou ld be of maximum reflectance.

Brightness contrast from surfaces of arying reflectance

Color contrast

Totally glossy surface (202· glossy photo: 203 - mirror)

Totally matte surface (201 -carpet)

Totally glossy surface (202-glossy photo)

Dark glossy surface on a light matte background (205 - dark printing on white matte paper)

Light glossy surface on a dark matte background (204 . white printing on black matte paper)

Dark matte surface or a raised projection on a glossy back-ground (206· matte paint or raised lettering on glass

Dark matte surface or an in· dentation on a glossy back-ground (207 - grout joints in tile work )

Metallic glossy su rface on a dark matte background (208 -gold or silver printing on a dark matte book bind ing)

Il lumination at the mirror angle (parti cularly for mirror-like surfaces with no inherent cotor (203) which can only gain surlace luminance by reflecting a source or ill uminated surface at the mirror angle.

Illumination normal to the surface.

Illumination from other than the

mirror angle.

Illumination from other than the mirror angle.

Illumination from a uniform source of maximum size at the mirror angle.

Illumination from a uniform source of maximum size at the mirror angle.

Illumination from a uniform source of maximum size at the mirror angle, or from a concentrated source from the viewing angle.

Illumination from the mirror angle.

Same as above except that a full spectrum source should be used for discrimination between a full range of colors; a limited spectrum source may be acceptable for discrimination between a limited range of colors.

54

'-.-' Task area

Illumination from a source within the mi rror angle. If such sources cannot be avoided, the negative effects of mirror reflections can be minimized by using sources of maxi-mum size and min imum luminance.

Illumination from a source within the mirror angle.

Illumination from a concentrated source at the mirror angle.

Illuminat ion from a concen trated source at the mirror angle.

Any illumination from outside the mirror angle.

work surface

Brightness contrast from variation in light transmission characteristics

Shape

Texture

Transparent surface (20 10· stained glass, and 3013· glass· ware)

Projected image (2012)

Translucent surface (2011· white glass)

Simple closed solid (301)

Closed solid with surface detail (302· sculpture, face)

Solid object related to other surfaces by cast shadows (303· ball in the a ir, steps in sunlight)

Simple open object under· standable in silhouette (304 . picket fence)

Complex open object (305 . wire sculpture)

Dark raised solid (307· dark raised letters)

Light raised solid (30B· light raised letters)

Totally glossy solid w ith no inherent color (30 11 . polished metal scul pture )

Moving solid (3012 · runner)

Surrounding enclosure (3014 · room, courtyard)

Simple rough texture (309· brick wa ll)

Complex rough texture (3D 1 0 . electrical circuits)

Backlighting from a uniform source.

Projection onto an opaque non· specular surface .

Backlighting; a concentrated source is acceptable if located some distance behind the translucent surface, unless the surface is closer to transparent than translucent.

Illumination from a single can· centrated source or diffused il lumina· tion with a dominant direction somewhat displaced from the view· ing angle.

Illumination from a single con· centrated source or diffused ilium ina· tion with a dominant direction somewhat displaced from the view· ing angle.

Illumination which creates a single sharp shadow.

Illumination wi th a dominant direction; multiple shadows are usually acceptable.

Single sharp shadow cast by a source located away from the view ing angle.

Concentrated or diffuse illumination from the viewing angle.

Illumination from any angle which produces consistent sharp shadows.

Illumination from a large uniform source at the mirror angle.

Il lumination wi th a dominant vector from the viewing angle such that it creates shadow grad ients on the object; best seen against a uniform contrasting background.

Illumination which clearly defines planes of enclosure with even light gradients, or to perceptibly different brightness levels.

Illumination from a single con­centrated source or from diffused sources at grazing angles.

Illumination from diffuse sources at grazing angles or from a concentrated source at neither grazing nor normal angles.

55

Backlighting from a concentrated source directly behind the transparent surface or object.

Stray light from other sources falling on the screen from any angle.

Overlapping shadows from several concentrated sources.

Illumination which creates multiple shadows, particularly if the shadows are cast from several different directions.

Multiple shadows.

Illumination from a concentrated source at other than the viewi ng angle, particularly at grazing angles.

Illumination from a diffuse source surrounding the object; supplemen· tary concentrated illumination can be used to create highlights, reducing the negative effects of a large uniform enveloping source.

Visual noise in the backgrou nd; min imize by locat ing potential sources of distraction such as light sources as far from the line·ot·sight as possible.

Illumination which upsets or destroys the visible form of surrounding sur· rounding surfaces, by co nfusing or distract ing illumination gradients which are inconsistent with the true form of the surfaces.

201

202

HOW WELL WE SE E

Object surface characteristics broken down

into two- and three- dimensional

categories

Totally matte surface

Totally glossy surface with inherent

color

203 - Totally glossy surface with no in­herent color on a dark background

204 - Light glossy surface on a dark matte background

205 - Dark glossy surface on a light matte background

206 - Dark matte surface or a raised pro­

jection on a glossy background

207 - Dark matte surface or an identation on a glossy background

208 - Metal lic gl9SSY surface on a dark matte background

209 - Metallic glossy surface on a light matte backgrou nd

2010 - Transparent surface

2011 - Translucent surface

2012 - Projected image

56

Table II

Matte photography, carpeting, embroidery

A slick magazine, glossy photograph, anything displayed under glass (prints, instrument dials) or found under water (an underwater sw immer)

Mirror , polished steel or aluminum, glass

Light printing on dark matte paper, a reflectorized highway sign

Printing, writing or drawing w ith ink o r paint on wh ite matte paper

Ridge or matte paint on an enamel, glass or plastic surface; a sw immer

on the surface of the water; a person seen against a wet street

A scratch on a painted surface, grout joints in tile work

Gold or si lver lettering on a dark book binding; printed circu its

Gold or silver lettering on a light book binding

A kodachrome mural or a stained glass window

White glass or plastic

Cinema projection, overhead projection, opaque projection

3D 1 - Simple closed solid with no internal detail (surface irregularities)

302

303

Closed solid with internal detail

Sol id related to other surfaces by cast shadows

304 - Simple open solid understandable in silhouette

305 Complex open s?1 id

306 Solid seen against a dark glossy background

307 Dark raised solid

308 Light raised solid

309 Simple rough texture

3010 - Complex rough textu re

3011 - Totally glossy solid with no in-herent color

3012 - Moving solid

3013 - Transparent solid

3014 - Surrounding solid enclosure

A ball or post

A face, topographica l globe, sculpture

Steps, ball in flight

Tree, picket fence

Wi re scu I ptu re

Pedestrian on a wet street, swimmer on the surlace of a swimming pool

Signs with dark raised letters

Signs with light raised letters

Brickwork, carpeting

Electrical circuits

Polished metal tools, silverware, polished metal sculpture

Baseball in flight, runners

Clear or colored glassware, colored liquids in test tubes

Room surfaces, courtyard

57

All the factors presented in How well we see are relevant to this

discussion. Very special conditions and combinations of these

factors exist for each type of object and for each type of activity.

Visibility and productivity Recognizing the many factors that influence visibility, we should ask ourselves these questions :

o When does visibility affect productivity?

o Is visibility the limiting factor? If so, to what extent?

o Assuming visibility is the limiting factor, is it logical to design

for the "worst condition" or the "most difficult task" which is neither important nor performed frequent ly?

If the visibility of an object is to affect productivity, the visibility

must be the limiting factor for performance. For typical school

and office activities there are no data to ind icate that productivity is affected by visibility as opposed to attitude, mood, mental speed,

motor limitation, concentration, distraction, etc. The exception

may be in viewing chalkboards, where poor visibility may some­times limit productivity. However, very large increases in light

strength must be made if they are to be as meaningful as a slight

change in physical conditions, e.g ., change of viewing distance, size of writing, or direction of light.

For industrial work, the situation where productivity is most af­

fected by visibility is in critical tasks such as watchmaking and in­

spection, where optical aids or special localized lighting is required ~ light with special characteristics in direction, color, focus, and

contrast.

Motivation and productivity Other examples of increased productivity due to improved visibili­

ty have been cited in the past, but are most likely in error since they ignore the Hawthorne studies conducted by Professor Elton Mayo of the Harvard Graduate School of Business Administration in the late 1920's.5 In these studies, production increased with in­

creased lighting, but continued to increase when lighting was re­

duced. Mayo's studies do not prove that increased I ighting cannot improve productivity, but they do demonstrate that productivity

increases are as likely to come from the feeling that mangement

cares about working conditions e.g. a better overall visual environ­ment.

5Weston, H. C .. Sight, Ught and Work, H. K. Lewis & Co., Ltd., London, 1962, pp. 165-66.

Mayo, E., The Human Problems of an Industrial Civilization, London MacMillan. Ro.ethl isberger, F. J, and Diekson, W. S., Management and the Worker, Harvard Univ­erSIty Press, copyrigh1 1939.

PRODUCTIVITY

59

"In industry, clear evidence of the effect of general illumination upon the

energies of workers has been obtained by Adams, who made a lengthy investi­

gation in the case of a simple occupation (making tiles) which did not requ ire

high illumination to make the work objects easily visible ... when artificial light­

ing was improved so that it contributed nearly three times as much light to

the presses and five times as much to the center of the shop, the output of the

tile pressers increased , on the average by nearly 6 percent. All the operatives

liked the new system of lighting very much because it made the shop look

more cheerful...the same operatives were then transferred to a newly con­

structed workshop where general daylight illumination was so good that art i­

ficiallighting was unnecessary. In the new shop the operatives aga in increased

their rate of working by about 6 percent. Adams concluded that this response

was chiefly due to the much more cheering conditions of Iighting ... 6

Saying it another way, the appearance of the space, rather than the visibility of the work , was cited as the beneficial element. As a result of the Hawthorne and Adams studies, we can state that any change (including physical) for better or worse, indicating at­tention paid to workers, can result in an attitude change in work­ers wh ich may subsequent ly increase productivity. I t is I ikely that change is more frequently brought about by improvement in over­all environment (producing a feeling of improved comfort and pleasure) t han mere improvement in "task" visibility . Thus, better colors, carpeting, or a more human environment from indirect or local lighting may wel l increase productivity more econom ically than increased footcandles.

Comfort and productivity In order to understand visual comfort and pleasure we need to ask, "What do we look at?" Even in factory production work, the eyes are not glued on the task at hand, but are scanning the environ­ment to perceive facts one instinctively or consc iously wants to know. At the other extreme, there are many spaces where formal activities are minimal or non-existent, and almost all of the visual activity is to satisfy biological needs (described in Chapter 4, along with corresponding information needs and hardware systems).

User surveys conducted by Manning and Wel ls 7 and Langdon8 in British office buildings show almost no complain ts about quantity of light (with levels largely below British I ES recommendations

6Weston, Op. Cit., pp. 162-164. Adams, S., " .The Effect of Lighting on Efficiency in Rough Work (Tile Pressing)". Joint ~~g5.lndustrlal Health Res . Board and Ilium. Res Comm. (D.S.I.R.). H .M.S.O. , London

7Manning. P. (ed). Office Design: A Study of Environment. Liverpool The Pilkington Research Unit, 1965.

8Langdon, F. J., Modern Offices: A User Survey, London, HMSO .. 1966.

PRODUCTIVITY

60

and even furthe r below U.S. practice). Complai nts expressed were most ly of discomfort glare.

The volume of work done by Hopkinson and others on discomfort glare also suggests a stronger relationship between comfort and the visual array of the environment than between comfort and the quantity of light. "Discomfort due to glare is not only a subject of complaint, but it is reasonable to suppose that it affects the general efficiency of the worker as a resu lt of a bui ld-up of an­noyance, frustration and irritation in people who are subject over a long period to what amounts to a minor emotional affront. It has been shown, however, that t he effect on human 'efficiency' is very difficult to measure, in much the same way as the effect of noise in a building is more important because of the distress which it causes than w ith the actual reduction of efficiency of work ing. "g

We are comfortab le when the objects we see give us the informa­tion we consciously or inst inctive ly want to know to carry out an activ ity or to satisfy a biological need. We are comfortable when we see we ll all the th ings we want to see-or when we see poorly, or not at all, all the things we do not want to see. The key factor in determini ng a desirable, comfortable luminous environment is relevance: relevance to activity and biological needs in a space.

Whenever a cheerful and bright space is expected during the day (lobbies, c lassroom, office, lab, library, etc.). large areas of wal ls or ce ilings must be ill uminated to balance daytime brightness (either visible simultaneously or remembered). Sufficient illumination of these surfaces w il l generally result in suff icient illum ination for casual activit ies throughout most of the room. Such "environmen­ta l lighti ng" plus supp lementary local illumination, controlled by the user for more demanding activities or in darker port ions of the room (e.g. in study carrels shadowed by enclosure). is likely to produce the greatest comfort both for those with local lighting and for others in the space- and at lowest cost. Increased illumination for the ent ire space is justified only if cri tica l tasks appear through­out the space and the geometry of I igh t ing, optimum for one occu­pant, is not detrimental to others in the form of glare.

Physical safety In normal lighti ng design, physical safety is a minimal factor, de­serving considerat ion only for exterior lighting at dangerous points such as stairs, and for interior ligh ting where very low light levels

are being sought as in nightclubs. At night a minimu m of 0.25 fc at any point from any direction shou ld be sufficient to prevent a person from falling, unless the visual informat ion is faulty (i.e. con-

9HoPkinson, Lighting of Buildings, p. 58 .

PROOUCTIVITY

61

f using shadows) or disabil ity glare conditions exist. This is demon­strated by the fact that these condi t ions exist without any appar­ent prob lems in a number of well-known buildings surveyed by Mr. Lam. In good design practice, where spaces that express their use well (mater ials, forms, focal points, junctions, stairs, etc., are de­fined) it is very unlikely that a safety hazard will ex ist except when glare sources are distracting. The average horizontal illum ina­tion level is not as important as the minimum illumi nation level, especia lly at cri tica l points where glare can create problems.

Another source of danger is disability glare f rom daylight sou rces, such as a window at the end of a long dark colored corr idor. In this case, the brightness balance shou ld be improved, either by additional lighting (achieved most effectively by illumination of l ight-colored ce il ing or walls, and/or reflect ive colors) or by con­trol ling the distr ibution of daylight. It should be remembered that, even with t he generally good brightness balance of full daylight outdoors, a dangerous situation will exist when one's line of sight is toward the sun .

Eye health "There is no genera lly acceptable evidence that poor illuminat ion results in organic harm to the eyes any more than indisti nct sounds damage the ears or foul smells damage the nose."l0 Eyestrain from trying to overcome a difficu It seeing condition is only a tem­porary d iscomfort and does not result in damage to the eye. The need for wear ing glasses arises only from organic causes. Eyestrain can result from glare as well as from inadequate illumination. Eye damage from light is possible on ly from overexposure, never from inadequate illumination.

10Cogan, D. G .. "Popular M isconceptions Pertaining to Ophthalmology," New England Journal of Medicine. 242: 462466. 1941. (Quoted from stenographic notes of SUCF Saratoga Conference.)

I n this chapter, biological needs are discussed and summarized in a master table, wh ich also includes perception-based criteria for various levels of act ivity . The format of t he master tab le is suitable for use in Space Program Charts (Chapter 5) and suitable for com­puter process ing. The charts may be used for var ious types of spaces. They should be kept current with changing needs and build ing programs, and should reflect feedback from user evaluations.

BIOLOGICAL AND ACTI V ITY NEEDS

Figure 55

Biological needs for

survival, protection,

and sustenance

Protection of the body - walk ing, runn ing, jumping

63

I nfDrmation awareness occurs through all the senses, but primari Iy

through t he visual. I naccurate or inadequate visual informat ion

can be distracting and even dangerous.

Satisfact ion level and pleasure from biologica l ly necessary stimu li

vary w it h cu lture, values, and opportuni t ies. Dissat isfaction , or

gloom, resu lts from any lack deemed unreasonable, not by choice

or in exchange for another advantage.

Percepti on of changes in locat ion, movement. and state is necessary

at all t imes for protect ion of t he body, even during sleep. Conti n­

uous visual contact is necessary for specific physical activities,

such as:

active: walking, running, jumping (percept ion of level, ground surfaces, obstructions, direct ion as in Figure 55) and worki ng (object of focus)

inactive: protection from physical attack (from ani mals, people, machines, weather, fire, and intense sound) and pro­tect ion of organs (parti cula rly sensory and reproductive) f rom physical damage, e. g. eyes from intense light.

BIOLOGICAL NEEDS

a. No horizon, no contrast

Figure 56 Protec tion of the body - horizon awarenesS

e. Clear horizon. but tilted (disturbing)

b. No horizon. high contrast

When walk ing, and even when seated , awareness of the horizontal is important. An unclear hor izon, because of low contrast, can be coped with . But we are uncomfortable for biological reasons when the horizon is not clear, as in Figure 56a: on a foggy day at the beach we are uncomfortable because the biological need for a de­fined horizon is unfulfilled.

BIOLOGICAL NEEDS

- -. -

-c. Horizon, low contrast d. Clear horizon

A familiar example of an uncomfortable space is in the TWA Term­inal at Kennedy Airport. Corridors leading to planes have slop ing f loors and non-vertical wal ls which cause disorientation, especially when there are no other people present for orientation. The use of vertical pictures or expansion joints would create a level which would reduce the unpleasant feeling in the space.

Another example is the Guggenheim Museum in New York City. Here people may be uncomfortable because they do not know whether to stand perpendicu lar to the sloping floor or parallel to the pictures wh ich are hung on a true horizontal.

Figure 57 Corridor at the T WA terminal

F igure 58 Guggenheim Museum

BIOLOGICAL NEEDS

Figure 59 Sustenance of body - t ime ori entation - daytime brighter outside than inside building

Figure 60

Sustenance of body - time or ientation - "G loom" when daytime not brighter outs ide th an inside building

66

The t hird biological need is sustenance of the body and our desired awareness of relevant informat ion . We are monitoring informat ion at all t imes, even though we are f reqent ly not conscious of some in for­mat ion we receive. We are more aware of bio logical ly, important fac­tors than we are of others which are less important to our we ll being, Some of these important factors are:

locat ion : in regard to water, heat, and food.

__ .!!t illm~e : biolog ical clock adj usted to day light cycle.

weather: for clothing, heating needs, long-term food supply,

hea lth-giv ing sun.

enclosure: air supply, co ld and heat.

opportun it ies: for relaxation of mind, body, senses; e.g. privacy, quiet, change of action to permi t maximum attention and alternates when necessary (for eyes - visual rest centers,

foca l poi nts) .

We are interested in and therefore alerted to the preceding fac t ors. Once they are part of ou r awareness, we eva luate them and if in­formation is ambiguous we are uneasy; if information can be c lear­ly interpreted we are 1) tense if the facts are dangerous, "bad," or a disappointment, 2) relaxed if the facts indicate everything is un­der control, or 3) pleased or even excited by cont rol and manipu­lat ion of elements essen tial for our ex istence (it is raining, but we need rain; there is a fire, but it is in a fireplace).

Because of t ime orientation, du ring the day we subconsciously ex­pect it to be br ighter outside bui ldings than inside as in Figure 59. At night we expect it to be darker outside buildi ngs than inside. We feel "gloomy" when the situation is ambiguous-every day at dusk or on dark overcast days, as ill ustrated in Figure 60. Length

BIOLOGICAL NEEDS

Figure 61

Sustenance of body - sunligh t : positive

Figure 62 Sustenance of body - sunlight: negative

67

of the ambiguous period is extended by use of low transmission glass.

Because we desire security from a surrou nding enclosure, clear understanding of the building's structure satisfies biological needs las does a view of sun light or an exterior landscape) and is per­ce ived positively. The ambiguous nature of luminous ceil ings IFigure 32) or rows of luminous f ixtures is likely to be found un­pleasant. Although uneven gradients positively defining the shape of so lid su rfaces seem pleasant and naturallFigures 26b and 28a), uneven luminance of a un iform flat mater ial seems unnatural and distracting IFigures 26a and 28b).

For some activ it ies, such as relaxing on a beach, sunlight may be all positive as in Figure 61. But, while we ali enjoy seeing signs of its presence, being in the sun light itself may have definite negative qualities if the ligh t or heat interferes w ith what we want to see or do, as in F igu re 62.

Figure 63 Sustenance of body - sunlight welcome: minimum inter­ference with activity

Figure 64 Sustenance of body - sunlight welcome: no glare

We can, however, we lcome seeing sunlight inside a building, as long as it does not interfere with our activity. For example, the patch of light on the floor in Figure 63 interferes with activity in only a small portion of the space. Direct sunlight on our desk or work area can be very bothersome-but only if we are unable to move away from it or control it and are exposed to it for a long period of time.

In Figure 64, the pattern of l ight on the walls is seen as sunlight. The edge of the ceil ing is open to the sky (visually) and connected

BIOLOG ICAL NEEDS

Figure 65 Sustenance of body - not seen as positive sunlight, but as glare

Figure 66 Protection of the body - 3014 - surrounding enclosure

a. L ighting confusing for p layers

-•

by beams (structu rally). Therefore, the su nlight is welcomed in­format ion, not "g lare," as wou ld be produced by trans lucent light f ixtures of equa l lum inance. The back lighting produced by the translucent panels in Figure 65 is not seen as natural sunlight but as informationless unnatural distraction-more frustrating than pleasurable, therefore "glare."

In certain sports awareness of hor izon becomes less important; clarity of the surrounding enclosure assumes top priority for the players, and light ing should reflect this. In the handball court in Figure 66a, definition of wall/cei l ing intersection is confusing for the handbal l player who plays against the ceiling as well as the walls. In the squash court in Figure 66b (where the ceiling is not a playing surface) definition of playing surfaces is not confusing to the player, even though lighting fixtures are similar to those in 66a .

b. Lighting not confusing for players

BIOLOGICAL NEEDS

Figure 68 Biological need - orientation: figure/background conflict

FiglJre 69 Protection of the body - active: edge emphasized by chan!';le in materials

70

When inside a room at night, looking at a dark window bright with reflections of the room, we perceive the window as "darker" than an interior wall of lower luminance. The wall is non-threatening,

but the window is a source of possible danger since we can be seen through it but cannot see outside.

Backlighted signs (such as EXIT signs, important for satisfying biological needs for orientation) frequently produce a figure/back­ground problem with the background shape reading much more strongly than the words within. This problem is avoided by using illuminated letters against opaque backgrounds (Figure 68).

• . I ~ , 'j

' i'

•

... ..... ' " ... , .

• j

•

-- ,

A person on the walkway in Figure 69 is very much aware of the water's edge on one side and the wa ll on the other. Several points are illustrated :

inherent biologica l needs: attention drawn to edge as a pos­sible source of danger; awareness of location to water

object clarity: edge emphasized by change in materials (especially important when illumination is or must be mini­mal because of confl ict ing demands. such as experienced in a theatre); sloping shadows add positive information, sup­porting awareness of stair risers.

BIOLOGICAL NEEDS

Figure 70 Biolcgical need - orientation: relevant focus

Figure 71

Biological need - orientation: relevant focus, gloom avoided. no visual noise

71

Examples of our need for spatial orientation and ways to meet it are given in Figures 70 and 71. In Figure 70, illumination of the instrument panel is from an angle to minimize negative reflections; focus in the room is where it should be (not on a ceiling full of light fixtures). The usual complex clutter of light fixtures in kit-

·1

chens has been eliminated in Figure 71, and the space is organized

by arranging indirect lighting around the "hood islands:" the il­luminated ceiling adds spaciousness and helps avoid "gloom" during the day when a bright "sky" is expected.

Table III is a master table of biological needs. It summarizes the visual environment and hardware systems associated with various biological needs. Also included in the table are descriptions of the critica l time/situation of each need and the relevant visual infor­mation.

" N

< < in' in' c: tll

c: !!!. o· !!!.

(") 3' 0 ~ 3' .....

'" ;:;. .....

0 c;. ~ c;. ~ 0 ~ ;:;. '" ~ 3 !!!. c: !!!. .c 3

'" :I '" ~ c: '" !:t ...... co ~ _. ~

_. 3 ~ _. 00'" g Q (1) '" 0 :I ~ 0. 0.:1

Physical secu rity When danger is ex- Location of potential peeted from people threats; the nature or animals of the surrounding

enclosure

When danger is ex- Comprehensible peeted from structural structure with clear failure continuity and visual

logic

When danger is ex- Location of control pected from fire and prevention equ ip-

ment; escape routes

clearly visible

~

::r '" en _ "C

c: '" '" 3:1 !? 6 :5' 0..< :"!

~.., 0 ;. en' n ~r+ c: cot: C" c.. ~ III =t' e!.. o' :;; '" _. _. 0 OJ~ ~ 3:::J (Q

@ co :5. "C 0' (=)' cnC") a ::.., Q)

<!:t.:::J g3 -~o 3 ~'" :I =- ::::J _. .... co ... Q) CD ..... 0 _ ...... ctI 30:1:10:1000. CII ..... C. ... ..,cn::::J..,cn

'" :I ::r s. 3

ClIO) "'c "C <~ 0 3 :: CII c.. ::J ..... C")

S:EQ)3:i"Q~ 3 ~ ::::I ~ 0 ..... O· CII<DC. .... ~~~

~ ~ ----Desired qualities Qualities to be avoided

Eliminate unlighted areas and sources of glare which might conceal danger;

clarify the nature of the surrounding enclosure -- structure, possible exits, etc.

Use forms consistent with the expec- Avoid flimsy structural forms such as

tations of the viewer; use light grad· the typical luminous ceiling; avoid ob-ients consistent with the form of the scuri ng structural elements with un-structure which they illuminate sh ielded light sources; avoid using

sou rces inconsistent ly (different sources to light identica l suriacesl

Use lighting to articulate circulation Avoid unevenly illuminated EXIT paths and ex its; use color coded fire signs, EXIT signs which do not dom-

extinguishers and clear EXIT signs inate their surroundings sufficiently to be clearly visib le; elim inate other

signs in the vicinity of EXIT signs

which would compete for the visual attention; avoid over ly bright EXIT signs, on the other hand, in dark en-

vironments such as theaters

2:' o r o Gl ()

l> r z m m o '"

0;1 c­eo

Orientation

Relaxation of the body and mind

v w

When danger may be caused by intense light or glare

When danger might be ant icipated due to un­sanitary conditions

At all times; maximum when moving

During sleep

Maximum evidence of high sanitat ion standards

Level horizonta l reference clues

Definition of ground surface contours, en-closing boundaries, obstruct ions, level changes

Location relative to destinations and exits

Only that required to mainta in the sensation of security; uniform condit ions of light, sound and temperature desirable

W W

Emphasize clean work areas in kitchens, labs, etc.

Use material joints (e.g. in masonry), moldings, expansion joints, mull ions, etc. to estab lish clear horizontal orientation

Define level changes and edges with highlighting, consistent shadows, changes in material (color, surface, or reflectance)

Articu late the bu ild ing layout and circulation system by a clear differ-entiat ion of circulation nodes and destinations with distinctive patterns of decorative light sources or by selective high light ing of elements such as elevator cores, etc.; corridors shou ld be differentiated from work spaces, and d ifferent types of corr idor should be treated d ifferently; good graphics should be used, particu larly at decis ion po ints such as corridors and inter-sections

Provide night lights as required for security; switching hardware should be readily accessible

w

Use proper glare shields or other contro l devices on luminaires so that sources do not achieve an undesired prominence or create disability glare conditions while providing required illumination for tasks or biological needs

Avoid highlighting areas such as dirty d ish conveyors or garbage collection areas

Avoid inclined floors without clear visual information defining the nature of the incline; spaces defined by ir-regular or curvilinear enclosing surfaces without clear horizon clues

Avoid distracting elements in the visual field at level changes; avoid confusing elements such as inconsis· tent shadows or carpet patterns which tend to obscure rather than empha-size level changes

Avoid undifferent iated lighting schemes which apply the same design to functionally disparate spaces, pro-vid ing no visual guidance information

Avoid back lighted signs with opaque lettering, in which the shape of the background typically dominates the intended message

Min imize the number of obtrusive luminous signs visible from sleeping areas; avoid street lighting with poor glare control

v

Adjustment of the biological clock (time orientat ion)

Contact with nature,

sunlight, and with other living beings

Definition of personal territory

\V During work

While awake but waiting or idle

Continuous need, particularly strong in unfamiliar situations

Interior environments

\1/

Particularly in public or work environments

Interesting v isual rest centers desirable

Interesting visual env ironment

\1/

Awareness of the state of the diurnal cycle, si nce luminous condi­tions in interiors are eva luated w ith refer­

ence to external conditions

Evidence of sunlight in every space or in nearby and accessible spaces

Visible ev idence of personal contro l and occupation of territory

\17 Provide visual foci such as views, art­work, positive expression of structural form, decorative or orientation-re­lated patterns of light sources (chan­deliers, graphics, illuminated sculp­t ure)

Provide visual foci as above; ev idence of sunlight, plants, water elements such as pools or fountains, etc.

Views of exterior conditions should be possible via clear w indows or clear skylights

Visible daylit or su nlit surfaces such as plant mater ial or w indow reveals; also daylit or sunlit meaningful translucent surfaces such as sta ined glass or colored glass block

Provide local lighting which can be controlled by users; provide distinctive or large-scale organization of the visual environment w hich can be used to locate and identify personal territory from a distance

Eliminate competing sou rces of visual no ise such as glaring f ixtures

Minimize unsightly, unplesant, or irrelevant elements of the visua l environment, since their negative impact wi ll be greatest when the viewer has no conscious preoccupation

00 not design windowless spaces un­less the justi fication is c lear and the om iss ion serves some other need: i.e., in a museum or t heater; wherever possible, give a view of more than jlIst sky

Avo id excess ive direct sun light on work surfaces; avoid information less distracting surfaces such as translucent windows and skyl ights; sun co ntro l devices if required shou ld create minimum visua l noise and f igu re/ background conf lict with t he view (i.e. large-scale louvers or fine-mesh screening rather than intermediate­scale egg crates or bl inds with no in­herent visua l interest)

Avoid public or work environments with no inherent means for personal­ization of space by the users

BIOLOGICAL ANO ACTIVITY NEEDS

Activity needs

75

Taking a close look at activity needs, all spaces contain activities

which have:

o sub-activities, which have:

o visual sub-activ ities, which have:

various information needs from objects of varying character­

istics

In general, many activities are carr ied on in a space. Each activity exerts conflicting demands for optimum performance - for d if ­

ferent aspects of the activ ity as well as among different activities.

As a result, there are constan tl y changing priorities of attention

and behavior objectives: lecture versus projection ve rsus note­

taking; concentrat ion versus relaxation . The following is given as

an example (see also Space Program Chart in Chapter 5):

Space

Activities

Sub-activities

Visual sub-activities

Information needs

lecture classroom

lecture, discussion, demonst ra t ion

listening to speaker, music or mean­ingful non-verbal sounds; tak ing not es, movement, relaxat ion ..

looki ng at faces, gestrues, clothing, notes visua l aids.

same as above

I n order to determ ine the appropriate characteristics of hardware

systems to be employed, each activity must be located in the space

and its requ irements ana lyzed:

o is the object of the activity vertical or horizontal?

o is t he object local or throughout the space?

o is t he object seen by va r iation in ref lectance, colo r, tex ture, shape, or a comb ination?

o is the object two-or three-dimensional ? G lossy or matte?

light or dark?

Various types of informat ion needs and object character istics and

relevant lighti ng cha racter istics (listed in Chapter 2) combine for

act ivities and sub-act ivities and must be summarized for the de­

signer in each T ypical Space Program Chart (sample in Chapter 5).

At f irst glance the chart appears impossibly comp licated and for­

midab le when , in fact, any t houghtful and exper ienced designer instinctively processes such data in every design decisio n.

Part I of this report has shown that many factors influence and de­termine biological and activity needs. These needs, in turn, in­fluence and determine the design process. The design of a success­ful luminous environment cannot be filtered down to fit one sim­ple formula. Numbers can be helpful in establishing criteria, but designers must be able to use their own judgement, since most criteria on which they base designs are themselves judgement­

based.

With Part I serving as a background to develop understanding of the processes involved in perception, Part II will show how judg­ment-based criteria can be developed easily and effectively. The designer can use these criteria to implement an optimum lighting design. The text in this part is divided into three chapters: Chapter 5 and Chapter 6 discuss how criteria can be established; Chapter 7 describes how the design can be imp lemented and evaluated.

PROGRAMMING

Purpose of the space program chart

Procedure for filling in the chart

79

The first step in establishing lighting criteria for the design of a given space is to program the activities for that space. This can be easil y done by filling in the b lanks on a Space Program Chart, a sample of which is given at the end of this chapter. The program­mers and/or designers are the most appropriate persons to com­plete the Space Program Chart. Those wish ing to apply this ap­proach to l ight ing design should find that after an initial period during which charts are developed for most all spaces sufficient experi ence will be ga ined so that much of the work can be done mentally. A blank chart has been included as Appendix F.

The Space Program Chart, Figure 72. is a comprehensive summary of all relevant criteria (except cost) that a designer needs in order to begin preliminary plan ni ng of the lighting for a part icular space. It is intended to serve as a means of communication among the de­signers. clients, facility users. and programmers. It can be the basis for developing and evaluating design alternatives.

The chart is divided into three main parts: 1) Biological and Activity Needs 2) I nformation Needs. and 3) Hardware Systems

The specimen chart included in this chapter has been filled out so that the reader can see a completed chart and be able to follow t he procedure recommended. By maintaining a file of completed charts, an entire series will be developed which can be continually monitored and revised as designs are evaluated.

They shou Id be prepared with the advice and assistance of the in­tended users: teachers, staff, students. and administration for ex­ample. The designers working with these persons will add the ir own input with the client having final approval

The format of the chart is designed for computerization. For any visual sub-activity (Item "F") most object and hardware character­istics in subsequent columns (p through u) will be the same. There­fore. when designing new space charts (or editing current ones) users. designers. and other non-technical personnel only need to describe behavioral situations (biological and activity needs and visual sub-activities, locations. and combinations with priorities). Subsequent technical facts (such as information needs. object cha racteristics, and hardware system s) can them be retrieved from computer files.

To assist the reader in the use and understanding of the chart. the following step-by-step procedure is included.

PROG RAMM I NG

Basic data (top of chart)

Biological and activity needs

80

a.

Space: room name or use, e.g. typical classroom/lecture, dining hall, etc.

Behavioral Object ives: list objectives in order of importance, e.g. 1) productivity, 2) morale & motivation, 3) resource uti l izat ion; or 1) enjoyment, 2) pleasure, 3) friendly, intimate atmosphere.

Biological needs: refer to Chapter 4, Table III , "V isual Envi r­onment and Hardware Systems for Specific Biolog ica l Needs."

b. Activity needs and sub-activ iti es : e.g. discussion, writing, read­ing, or lecture (seeing and hearing speaker, seeing chalkboard, movie screen, etc.).

c. Part ic ipants: list the various categories of persons using the space, and place a dot in line with the visual sub-activity they will engage in. Other graphic designations used in the chart are good (+), bad (-), or critical (x). (Anything termed crit ical requires a numerical factor in Item "t.")If a space is left blank, the factor indicated is not a problem and is of less importance to that specific condition.

d. Priority: activity and biological needs ranked by percentage of relative importance and duration; total must equal 100%. For example, priority in a typical corridor might be as fol-

lows: lent, relaxation, stimulation 70% visual communication (bulletin boards) 10% displays 10% cleaning 10%

100%

However, if the main function of the corridor is a gallery for art work, the priorities might change as follows:

movement, relaxation, stimu lation visua l com munication (bulletin boards) displays of art work cleaning

40% 10% 40% 10%

100%

e. Visual sub-activities: underline two most important aspects necessary for achieving Behavioral Objectives.

f. Vi sual obj ectives: list the various objectives necessary for the activity within the space; e.g. faces, gestures, TV screen, sculpture.

g. Events: indicate possible combinations of visual sub-activities by list ing events and possible combinations of simultaneously occurring activ it ies for each event; e.g. a lecture, with slide

PROGRAMMING

Information needs

Hardware systems

81

presentation and cleaning. For listening to the lecturer as well as seeing visual aids and notetaking occur simultaneously. Looking at projections and handwriting are simultaneous visual sub·activities; therefore, light for notetaking should not spill on the screen . Cleaning is not simultaneous with any student/teacher sub·activities; therefore, supplementary high· glare lighting that would not be used for normal classroom activities could be provided for cleaning.

h. Priority: as in "d", percentages should be assigned according to importance of or duration of activities.

I. Location: horizontal or vertical plane that must be lighted (with either general or local illuminationl for each activity.

J. Remarks: any unusual aspects should be noted here.

k. Required information: underline the most important aspects necessary for carrying out visual objectives.

I. Object characteristics: from Table II , fill in 20 and 30 characteristics which match the visual objectives listed in Item "f."

m. Information needs: place a dot in each blank which satisfies the visual requirements of persons using the space; e.g. in a lecture hall, reflectance, form, and texture are necessary, lighting color should be non·disturbing but color accuracy is

not essential.

n. Negative factors: within the context of the space program, conflicts in lighting requirements must be controlled. For example, in a lecture hall, it should be possible to see the speaker's face and take notes during a slide presentation. Similarly, cast shadows must be controlled so that the speak· er's face is not in shade and the person is not writing in his own shadow.

o. Characteristics of visual environment: underl ine the most

important aspects.

p. Characteristics of prime light source: subdivided into Items "q" through "t."

q. Dominant light direction means a strong direction from the light source. The normal angle is not normally checked since it coincides with the mirror angle in actual situation. If the

PROGRAMMING

Footnotes

82

relationship is fixed, or if there is a total ly matte surface, the normal angle is acceptable. Angles to surface and viewer apply to 20 only, si nce the grazi ng angle for 3D objects means per­pendicular to the viewing ang le. If, in the lighting position rel­

at ive to the surface, the grazing angle is minus (producing excessive modelling) and the normal angle is minus (mini ­

mizing texture), then the best posit ion is somewhere between them. Polarization is useful for increasing contrast rend ition only when the light source is both approaching the grazing angle (l ow angles, above 600 , to the surface) and at the mir­ror angle to the viewer. One of the few ti mes these conditions are met is du ring certain drafting act iv iti es when the work cannot be moved.

r. Size of sou rce : indicate maximum (diffused), minimum (con­centrated), or combination of both relative to object bei ng

lighted. Size indicates a so lid ang le subtended from the object and is not a question of physica l size of the light source.

s. Wave characteristi cs: Note where polar ization or fu ll spectrum is particularly valuable: when accurate color rather than non­disturbing color is needed (such as for color matching and for ce rta in types of medica l examination). Parti al spectrum may someti mes be usefu l (e.g. ultra-violet, infra-red, red light, blue light), but most activi t ies simply require non-dis­turbing color (see Chapter 2).

t. Remarks: unusual requirements for the space to be designed should be listed here. For example, continuous or stepped dimming, eli mi nation or add it ion of ligh t in a certa in area, maximum or minimum conditions, wide or narrow range of flexibility.

u. Numerical crite ria: units of measurement, relevant to the var ious hardware systems, are used for comparison of al­ternate systems and as a requirement when the factor is defined as crit ical . For Biological Needs, criter ia such as a

Semantic Scale (see page 83) w ith no required value, should be used. I tems tha t most closely measure achievement of the relevant In formation Needs (Item "k") could be underlined and used as a reminder of what to think about when review­

ing final design decisions.

Any unusual condit ions or circumstances or requirements not ind icated elsewhere in the chart should be noted here.

A final word abou t the sub-activi ty "cleaning" : if, in Lighting Budget Ca tegory A, B, C, or 0 (when darkened space is not an ob­iective) conditi ons and requirements are met, cleaning require-

PROGRAMMING

Units of measurement

Space program chart information

Notes

83

ments are simultaneously satisfied . Special consideration is neces­sary only in spaces which are normally dark (such as an auditorium , corridor in a gallery, etc.) in which case a separate or portable l ighting system for cleaning may be necessary.

DR Directional Ratio

FC max

FC min

Maximum illumination on object

Minimum illumination on object

BR Blackout Ratio

FL on

FL off

Screen luminance - Projector on

Screen luminance - Projector off

CR I

RCS

EFC

SF

A

Co lor Rendering Index

Relative Contrast Sensi t ivi ty

Effective Footcandles·

Shadow Factor

Sample semantic scale

Clear Confusing Safe Dangerous Pleasant Unpleasant Orderly Disorderly Restful Distracting Relevant Irrelevant Natural Interesting Cheerful Too bright Spacious Leisurely

Unnatural Dull Gloomy Too dark Crowded Rushed

B Symbol definition

1.

Relevant + Good

Bad x Critical

Column f. Unit of Measurement - SF - Shadow Factor.

Amount of reduction of illumination from shadow; required when visual activity is crit ical and viewer or object cannot move.

2. Column g. Activity Needs and Sub-activities.

"Discussion" and "conversation" are different degrees of the same ac­tivity: the former more formal; the latter more informal and requiring a lower level of illumination.

"* Definition yet to be developed

PROGRAMMING

Use of the chart

during the design

and review processes

84

"Reading" and "browsing" are a similar situation: each require a dif­ferent ReS (generally lower for browsing), which may change with priority (the higher priority, the higher criteria required).

3. Column n. Location - Both local and general locations are indicated in some instances - the designer is to decide which applies for a specific space.

In this section, questions have been listed which are typical of the

mental process the designer should employ when reviewing the classroom/lecture room example described in the previous section.

It is emphasized that this questioning procedure is not required of

the designer, but is included here because of its obvious applica­

tio n to the general design and review processes .

•

From t he example, a designer may reasonably conclude that dis­tribution of resources should favor indirect illumination of room

surfaces as well as of activity focal surfaces (at front of room and vertical surfaces facing students) to meet expectation of a bright,

cheerful space. This system will illuminate people and other ver­tical surfaces, from favorable directions (neither grazing nor nor­

mal) and satisfy needs: Biological (such as lack of distraction and

daytime reference expectations) and Activity (vertical surfaces

and people rather than maximum focus on desk tops through­

out space). The 10: 1 blackout ratio requirement means the ability to exclude daylight totally, and a separate low level dim­

mable downlight system to illuminate desks without illuminat­

ing the projection screen. Incandescent downlights could sup­

plement the diffused lighting from walls and ceilings as a small source component . This would be useful for modeling form and

texture, but will have the negative side effect of casting shadows.

1.

2.

What is the importance of seeing room surfaces and people vs. desk tops and other horizontal work surfaces?

Illumination a. General or local? b. What portion of space requ ires local

light' c. Locations fixed or flexible?

d. Horizontal or vertical?

(Biological needs are mostly vertical.)

3. Will a single hardware system suf­fice or must alternative systems be provided?

a. What are the simultaneous use grou ps/su b-activiti es?

a.c,f,h

d,k,h,i

f,g,h

b. Are the needs of the simultaneous I,m,n

4.

use groups similar?

c. Are the needs compatible with a single possible hardware system or do they require design separation, dimming, etc.?

Are there critical conditions w hich must be met?

a. Ability to exclude daylight totally (10: 1 blackout ratio)7

b. Avoidance of cast shadows?

g,r,s,t

t

d,h,j t,u,n

n

c. Angle of prime light sources? q

d. Size of prime light sources? r

e. Color needs? Critical locally or generally?

m,u

d,k,h,i

(% from typical classroom/lectu rel

77% VS. 23%: suggests illumination of room surfaces (chalk boards, walls, and ceiling), which are in turn good sources for illumination of people.

To evolve lighting and furniture concept which, in this example, is an irregular (rather than uniform) lighting layout w ith recognition that the majority of information needs are vertica l and in front of the room.

General 27% Horizon. 17 Y:z% * Vert. 9Y:z% *

Local 43% 8%

35%

·Cleaning (5%) divided between horizontal and vertical.

Conflicting needs and a variety of simu ltaneous activities indicate a need for variety in the visual environment. Several hardware systems, or a single system with adaptability by switching and dimming, are required.

Design must accommodate these cri tical conditions.

Projection, with a 10% priority, is important enough to have good black­out provisions. If priority had been 1 %, worst conditions (5: 1 ratio) may be acceptable. But if this is not acceptable. the activity might be programmed for another space, depending whether the need is for a few moments frequently or for longer periods occasionally.

Critical at chalkboard 10% because audience cannot move. At horizon­tal surfaces 5% because even though important, work can be moved.

Non-disturbing color 37% - important but no needs exist for accurate color.

In establish ing t he lighting criteria for a given space, the first step is to program the activities and sub-activities. The second step is to ass ign a budget for the lighting in the space.

The budget system presented in t his chapter is to be submi tted with the Space Program Chart, which it supp lements. The system is both simple and flex ible, resulting in meaningful information fo r the designer.

LIGHTING BUDGET

The lighting budget system

9 1

The optimum level of user satisfaction from a given lighting envir­onment resu lts when the designer has achieved maximum per­formance in many ways, rather than simp ly in the quantity of il­lumination provided. The system fixes the l igh ting budget by tak­ing this into account, so that the best design can be obtained w ithin the available means-both financial and technologica l. The system assures some important advantages:

Improvement in visual environment is not likely to be re­stri cted by oversimpl ified tech ni cal criteria .

Equal quality of visual environment is promoted among facilities under the same jurisdiction.

Equality of design challenge is offered to all designers.

Comparative assessment of buildings (and their designers! IS

put on a releva nt but cons istent and impersonal basis.

The proper balance between comfort, du rab il ity, appearance and cost must be determined and a budget system is necessary .

A budget system of some kind is necessary so that the proper blance between comfort, durabil i ty, appearance, and cost can be determined. A capital cost budget is not considered most effective as the primary measu re for judgi ng a lighting design because it does not encourage the most eco nomica l l ife cycle so lution and it is difficult to administer at the time when de­sign decisions must be made.

The most appropriate budget is one based on generated light -the amount proportional to room surface area and reflectances,

that is deemed satisfactory to meet the needs of the pro­grammed activities and objectives. This budget system allows the designer to do detailed lighting design, select fixtures, etc., late in the design process, after schematic solutions have been developed and approved. Such a budget also forces early recog­nition of the beneficia l effect of room reflection (proper choice of materials! on light ing costs.

Budget requirements are also ad justed for anci llary factors in­cluding daylight contribution, minor room-to-room variations, in­crements in lamp sizes, and geometric arrangement problems. For simpl ification of data presentation, budgets are defined as being in one of several categories. These categories are explained in Table IV, Lighting Budget Categories. Following the table is the L igh t ing Budget Conversion Graph Figure 73a, based on 1973 lighti ng industry standards, and Figure 73b (for energy conserva­tion! with scales set to reflect a 25% reduction in 1973 industry standards.

Table IV

92

A

A+

B

B+

I: o ''::; Kl 0." .- co ~ 0. ~ '" CIl ....

Cl 0

Spaces with critical visual activities distributed through­out space and where a bright space is expected: labora­

tories, general offices, drafting rooms, studios.

The same type of spaces as in "A," but with additional requirements in localized areas which are designated in

the program: operating room with adjustable sup lemen­tary illumination over the table in a fixed location.

Spaces with normal visual activities evenly distributed

throughout the space with moderate brightness expec­

tations: library/stacks., seminar and conference rooms,

gymnasia.

Spaces in which critical visual activities are fixed or where

local supplementary lighting can be easil y and conven­

iently provided: reading areas in library stacks, labora­

tories or shops with special equ ipment at fixed locations.

C Working spaces with no unusual biological needs but

with expectation of moderate daytime brightness for

modest visual activities where the occasional normal or

critical visual activity does not have suff icient priority

to justify additional lighting : circulation spaces with ac­tivities (lobbies, lounges). cafeterias, exercise rooms,

locker rooms, or swimming pools.

D Active spaces with minimal visual activities or length of

occupancy, and where feelings of safety, rather than

cheerful brightness, is expected: active circulation spaces such as corridors, stairs, foyers; active storage areas.

E Infrequently used utility spaces: maintenance corr idors,

inactive storage areas.

TV Only used for spaces where network quality color tele­

vision coverage is frequent enough to justify permanent supplemental lighting for that purpose. When deemed

cri tical, such I ighti ng wi II be determined in consu Itation

with the networks. (Since it is not reasonable to use this supplementary lighting except when televisi ng, flexible

switching shou ld be provided.1 For intermittent coverage,

it is expected that networks will supply their own sup­

plementary lighting when necessary. It should be noted

that normal room lighting is sufficient for monitoring.

In recognition of the irrelevance of small increments of light to the

improvement of performance, it should be pointed out that these

categories represent noticeable steps, each with two times the light input of the former.

LIGHTING BUDGET CONVERSION GRAPH

SCALES SET TO REFLECT 1973 INOLSTRY.STANDARDS a V> . 80 \ '" z

I ...J - .75< I UJ u a \ ii;: V> .70 \ ...J

\ ...J <{

'" LL .65 ' \ 0

UJ \ u ii;:

.60 , \ >-u UJ \ ...J LL UJ \ '" .55 UJ \ '" <{

\ '" UJ

'< .50 \

. 45 ' \ \ \

.40- \ \ \

.35 ' \ \

.30 \

.25 "\

----~---LIt-1lT FOR BUDGETS ' A' AND 'B' (WITHOUT DEJVoONSTRATION OR MOCK-UP)

'\ .20 '\.

'\ '\.

'\. . 15 '\.

'\. "-

.10 "-

.05

LIGHTING BUDGET A 0 50 100 150 200

LUMENS PER SQ.FT. OF ROOM SURFACE AREA ( WALL, CEILING,FLooR ) LlGHTING BUDGET B

25 50 75 100

LI GHTI NG BUDGET C 5 10 15 20 25 50

LIGHTING BUDGET 0 0 5 10 15 20 25

Figure 73a

93

LIGHTING BUDGET CONVERSION GRAPH

b <f> <.!) z ::i W u 0

il' <f> ...J ...J

~ LL 0

UJ u il' f-u UJ ...J LL UJ

'" UJ

'" <l:

'" UJ

"

FOR ENERGY .80 ..

.75

.70

.65

.60

.55

.50

.45

.40

.35

.30

CONSERVATION: SCALES SET TD REFLECT 25% REDUCTION IN 1973 INDUSTRY STANDARDS 1

\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \\

\ LIMIT FOR BUDGETS '-, A"""""-AN-D ~"ITHOUT DEMONSTRATION OR MOCK-UP)--

'\ .20 '\.

"-.15 ~

"-. 10 "-..........

.05

LIGHTING BUDGET ~O~----.------r-----.-----.r-----.-----.-----.-----~~--------------• • 20 40 60 80 100 120 140 160 LUMENS PER SQ.FT. OF ROOM SURFACE AREA C ¥lALLS, CEILING, FLOOR )

10 20 30 40 50 60 70 80 LI GHTING BUDGET B

LI GHTING BUDGET C 5 10 15 20 25 30 35 40

LIGHTING BUDGET 0 o 5 10 15 20

Figure 73b

94

LIGHT ING BUDGET

Appl ication of the lighting budget system I

95

The fa Ilowing step-by-step procedure is included to demonstrate efulness of the Budget System in actual design and evaluation ons.

the us situati

Step 1

Step 2

Step 3

Step 4

Step 5

Step 6

Step 7

Determine the category (A, B+, etc) of the space to be designed using Tab le IV, Light ing Budget Categories

Determine the generated lumens per square foot of room surface area (f loor , wa lls, cei ling) using Figure 73, Light­

ing Budget Conversion Graph . This graph summar izes the applica t ion of categor ies for various reflectances of walls and ceilings. See Appendix 0 for reflectance values of common finish materia ls. To obtain the generated

lumens per sq uare foot of floor area only, ca lcu late the requirements for the room, then d ivide by the floor area .

To adjust for daylight, assume the ref lection of windows to be the same as for draper ies or blinds. If no light con ­

trol devices are provided , consider the re f lectance oj wi ndows to be 10%. Then su bt ract the dayl ight contr i­bution of unobstructed exterior opening from the re-

qu ired lumens of the room 300 lumens per square foot of open ing is multipl ied by the transmiss ion fac tor j ar

the glass (clear glass is 90%). But daylight can account for no more than 50% of the total lumen requirement,

since most spaces are used both day and night. It the sky exposure is obstructed , reduce proportionally .

Nighttime requirements are not as great as daytime re­

quirements due to a person's lower adaptation leve l and

br ightness expectation . Because of this, the amount of

generated light may be reduced up to 50% of daytime

levels for most act ive spaces, and up to 90% for many

spaces in Categor ies C and D . T his is easi ly accomplished

by switch ing and dimming devices.

Local Lighting (Category B+ ): if the most cr itical work

areas are local ized because of furniture and equipment

arrangements, spaces assigned to Category A may be

served more economically (and equal ly as well) by usin0

Category B plus supplementary local ligh t ing at critical

wo rk areas.

25% plus or minus variance is allowed in any space as an

adjustment fo r room -to-room va riat ions in ref lectances,

proport ions, and availab le increments in si zes of light sou rces.

Maintenance is planned at the minimum operating point of 50% of in itial output, and cost ana lysis is also figured

LIGHTING BUDGET

Step 8

Step 9

96

on this basis. This does not mean that the average will be 50%, for the average maintained illumination will ac­tually be 75%±. No design assumptions are necessary since the budget already takes into account the fact that the lighting will depreciate with the aging of,lamps and

the dirtying of surfaces.

Regarding lighting controls, provision of the budgeted light for each room does not require that the full budget always be used. The practice of reducing initial cost by placing switches to control large areas of a building, rather than individual rooms, is deplored. I t is wasteful of money and natural resources, and also prevents the visual environment from being relevant to any particu lar use of individual spaces. The best visual environment for wide ly varying activities can best be produced by sep­arate switching of each type of lighting component as the users, conditions, and activities dictate, i.e. for lec­ture, slide projection, or discussion; for full occupancy, single small group in a corner, or unoccupied room; for rooms or portions of rooms w ith more than adequate daylighting during daytime or nighttime use.

Better controls than typ ically provided are particu larly necessary in "loft" type buildings when a un iform pat­tern of ceiling lighting is prov ided to achieve maximum flexibility of partitioning and use. If the uniform light­ing pattern is composed of incandescent fixtures, the sizes of lamps can be varied according to the varying budget requirements. Although typical fluorescent fix­tures lack this adjustability, a wide range of adaptabi li ty can be ach ieved by use of three- level ballasts in all fluor­escent fixtures. If these levels were 100%, 50"10, and 20% of rated lamp output, a layout arranged to meet the re­quirements of an "A" category space can be instantly set for "B" or "C" whenever the use of the space is changed. An office designed for an "A" budget can be converted to "B+" by setting the fixtures over the desk area at 1 00% and the rest at 20%. For these infrequent changes, an easi Iy accessible switch can be suppl ied wi th­

in each fixture.

For rooms which can benefit from frequent changes of light ing, the various levels can be more conveniently con­trol led by low voltage switching.

The limitations in design (apart from budget) should be considered: a. Low Reflectance: average reflectance of less than 25%

is not permissib le in Category A or B spaces without

LIGHTING BUDGET

97

successful demonstration of a full-scale mock-up or through review of similar existing spaces.

b. Luminaire Efficiency: all luminaires must be 90% as efficient as the best commercially available product with similar light distribution and luminance patterns. Sacrifice of more than 10% for architectural design or mechanical features is deemed unnecessary. When in ­efficient decorative fixtures are used , the total gener­ated lumens in t he room should be increased accord­ing ly.

c. Radiant Heat: occupants should not be continuously exposed to excessive radiant heat from lamps.

d. Umiormityof Illumination Distribution: to avoid dis­traction caused by the upsetting of brightness constancy, smoothly graded illumination should not vary more than 2: 1 over 12 inches, or more than 3: 1 across the active portion of a working surface.

e. Shadows: to avoid distraction from shadows cast by the body or head when it is not convenient for the worker to relocate w ith respect to the work (ind icated on the Space Program Chart), a red uction in average lig ht level on the task of less than 10% is desirable; a 50% reducti on is the maximum permissib le. For evaluation, assume that a person occupies a rectangle 12 inches w ide by 24 inches high at the edge of a standard 30 inch wide table for a sitting position, and 12 inches w ide by 36 inches high for a standing position. For drafting, the shadow which is measured should be cast by a three-inch cube resting on the work surface.

f. Sound: Ballast noises should be minimized by use ot the most quiet type available for each lamp type. Th is is not limited to "A" category ballast rating, since fewe r noiser ba llasts may be equal in total noise gen­erated. L imitation is of to tal noise generated relative to ambient noise. Unfortunately, there are no indus­try -w ide standards for measurement of rating of bal ­last noise. Des igners should be awal'e that each manu­facturer defines his own ballast rating .

The design procedure used by some satisfies quantitative criteria only, and frequently leads to arbitrarily-selected lighting layouts. But the best designed lighting environment must be judgment­based with flexibl e criteria.

The design process outlined in this chapter emphasizes detailed participation by designer and client in open discussion and mutual decision-making, with thoughtful application of the principles of perception to programmed objectives. The process is presented in

the table on page 100.

Figure 75

Design pr.Jcess - rough model (used to obtain data as well as to predict appearance)

Figure 76

Design process - rendered perspective

Figure 77 Design process - fu ll scale mock-up

(showing two alternat ive lighting configura t ions)

\

DESI GN PROCESS Table V

I Space program

LIGHTING DESIGN

PROCESS

(bl Develops Space Programs for spaces outlined in facility pro­grams. Determi nes lighting bud­

get from chart.

2 Schematic design

(a) Analyzes architectural concept

of the building and visua l infor­mation needs for t he behav ior objectives. Develops a lternate schematic designs by man ipu la­ting plan and section, structural,

mechanical and electrical services acoustics, equipment, and furn · ish ings with respect to daylight

and artificial l ight sou rces. Elec­trical load requ irement s can be est imated as soon as reflectances have been determ ined .

(b) Simu ltaneou sly refines and de­

tails all of the interrelated aspects of t he schematic designs; delays development of details t hat are independent and can be done later.

(c) As the design solut ion is refined and ex periences change, insure that the lighting concept remains compatible with the latest archi­tectural thinking.

(d) Defines pattern and selects types of I ight sources and I ight control media.

(cl Space Program Chart

(e) Alternate design concepts are presented as rendered sketches, lighting layouts (not electr ical layouts), diagrams, models, mock-ups, or relevant field dem­onstrations to indicate how light­ing object ives will be achieved (see Figures 74 through 771;

{al Gives designer facility program

(d) Approves or disapproves.

4 Revisions

If project is over dol lar budget,

revise design as appropriate {re­peat relevant processes from Schematic design, Step 21.

5 Evaluation and feedback

101

Conduct user eva luation using Rating Sh eet, evaluate achieve­ment of detailed criteria based on behavior and affect ive perception requirements. Revise Space Pro­gram Chart or Lighting Bud!=, "" ... as necessary for next projt: i ,.

/ /

I

DESI GN PROCESS Table VI

RATING SHEET (COMPARISON OF ALTERNATE SYSTEMS] FOR

PROPOSED HARDWARE SYSTEMS

Needs A B C

(activi t y and b iological) * Prio rity% Rating % Rati ng % Rat ing %

1. Biological 30 8 24 3 9

2. Lecturer 20 8 16 4 8

3. Chalkboard 10 8 8 5 5

4. Projection with notes 10 10 10 3 3

5. Books, notes 5 8 4 10 5

6. Notetaking

with pro jection 10 10 10 7 7

7. Conversation 5 8 4 5 2.5

8. Control 5 8 4 8 4

9. Cleaning 5 6 3 10 5

Rel ative Performance 83 46 1/2

Relative Cost (bu ilding system -1 1

initial, operating, f lexibi lity)

Rank order judgment (on basis of

cost per unit of performance, satis-

faction , and weighted in context of

overal l proiect budget) 1 2

* as listed on Space Program Chart

103

This report should be of interest to those concerned with the lum­

inous environment. For some, the entire app roach may have ap­peal, for other individuals, part s of the report wi l l offer new in­

sights and perspectives. It is in this spirit t hat the report is being

made available as a publ ic service. It does not necessarily represent the single view of the Fund and is not mandatory for Fund pro­Jects

Applicat ion of this approach to l ight ing design should result in

energy conservation since it seeks ligh t ing designed to meet more

precisely the uses intended. Following this method wi l l avo id over­

design and waste of both capital and operating resources. In 1973

when t he final draft of this report was completed, the budget level

used (represented by Budget Curve 1, Figure 73a was based on the

then current industry standards. Budget Curve 2, Figure 73b (1975)

represents a 25% reduction in that leve l in response to the energy

crisis. As stated by Lam, even more significant savings can be made by maximizing the use of local lighting (Step 5, p.95)

Using lower overall light levels has merit since as Part I of the re­

port illustrates most activities can be accomplished with less l ight if the lighting is caref ully designed to meet the needs of the tasks to be undertaken in a particular environment .

Some portions of the process, such as the space program charts, may Justifiably seem excessively complex and time consum ing

if not done by computer. However, we bel ieve that the system is not significantly different f rom that employed instinctive ly by any good designer in approaching a problem , and that the

charts are invaluable even for the "non-computerized" designer

in demo nstrating specifically the kind of mental process that produces a good l ighting design .

The appendix of th is report provides background on t he work that

preceded this report. Further, for those interested in the lum inous environment, there is an extensive and deta iled bibliography.

This bibliography represents the range of subject matter that should be covered for an understanding of the luminous environ­ment. The list is by no means complete; rather, it notes the type of material relevant to such a field. Annotations are the personal opinion of Mr. Lam . Aster isks (*) indicate what could be con­sidered required reading for all those involved in programming per­formance criteria - architects, administrators and users.

BIB LI OGRAPHY I INDEX FOR APPENDIX A

109

1. Performance or phys ical specif ica t ions

2. Cr it ical analysis of performance specificat ions

3. Subjective eva luation of spaces and their components by ind ividua l and group samp li ng

4. Buil t environment

5. Design process

6. V isual environment criteria

7. Lighting cr iteria

8. Multi -var ien t research methods

9. Cost stud ies

10. Materials and engineering data

11. Task analysis

12. V ision research

13. Eye movements

14. Communicat ions theory

15. Perceptua l psychology

16. Co lor percept ion

17. Performance and fatigue

18. Stress-sensory deprivation

19. Visua l environment

20. Environmental psychology

21. Behav iora l science

22. Anthropology

23. Pub lic health and safety - ophthalmology

24. Education methods

25. Research programs, organizat ion summaries, bibliographies, indexes

BIBLIOGRAPHY I 1. Performance or physical specifications

Hopk inson, R.G., "A Proposed Luminance Basis for a

light ing Code," f rom Transactions of the Illuminating Engineering Society, Vo l. 30, No.5, 1965, pp. 63-88

Moon, Pary and Dom ina Eberle Spencer, Lighting Design, Addison·Wesley Press, Inc. Cambridge, Massachusetts, 1948.

2. Critical analysis of performance specifications

Educational Facili t ies Laboratori es, The Cost of a Schoolhouse, Educational Faci li t ies Laboratories Inc.,

New York, 1960.

Metcalf, Keyes D., Planning Academic and Research

Library Buildings, McGraw-Hi li , New York, chapter 9, "Lighting and Ventilating."

lighting criteria summarized by an inte ll igent cl ient.

Cogan, David, M.e ., npopu/ar Misconceptions Pertaining to Ophthalmology," N. E. Journal of Med icine, Vo l. 24,1 941, pp . 462-466.

3. Subjective evaluation of spaces and their components by individual and group sampling

110

"Appraisal of Light ing Qua lity", Illuminating Engineeri ng Society, Survey Check l ist.

Bitter , Coo and Van Ireland, J.F.A.A., "Appreciation of Sun light in the Home" , Research Institute for Public Health Engineeri ng, Publicat ion No. 242, Delft, Netherlands.

Canter, Dav id, "On Appraising Build ing Appraisals", The Architects' Journal Information Library, 21 Dec. 1966 , pp. 1550-1 597.

Chapman, Dennis and Geoffrey Thomas, " Ligh t ing of Dwelli ngs" , Wartime Social Survey , New Series No. 24, A tlant ic House, Holborn V iaduct , London, March, 1943.

The Effect of Windowless Classrooms on Elementary School

Children, Architectural Research Laboratory, Dept . of Archi tecture, University of Mich igan, 1965.

de Graaf , A.B. and J.C. van Lierde, " Appraisal of Lighting Instal lat ions," Unpublished paper.

Hewitt, Harry, " The Study of Pleasantness" , Light and Lighting, June 1963, pp. 154-164.

BIBLIOGRAPHY

111

Hewitt, H., D.J. Bridgers, and R.H. Simons, "Lighting and the Environment: Some Studies in Appraisal and

Design", Transactions of the Illuminating Engineering

Society, Vol. 30, No.4, London, 1965, pp. 91-116.

Lofberg, H.A., "Results from an Experiment with Subjective Appraisals of Lighting Quality in a Full Scale Model of a Classroom", Unpublished paper.

Manning. Peter, "Appraisals of Building Periormance and

Their Use in Design", unpublished paper.

Manning, Peter and Sheila Taylor, "Appraisals of the Total Environment", Pilkington Research Unit, Dept. of Building

Science, University of Liverpool, Dec. 1965.

Manning. Peter, "Appraising User-Requirements and Design

Criteria", Northern Architect, March/April, 1968.

Manning, Peter and Brian Wells, "An Example of the Semantic

Differential", Pilkington Research Unit, 30 May, 1968.

Manning, Peter, .. Lighting and the Total Environment". an

account of some studies by The Pilkington Research Unit,

Department of Building Science, University of Liverpool,

June, 1967.

Manning, Peter (ed), Office Design: a Study of Environment, Pilkington Research Unit, Department of Building Science, University of Liverpool, 1965, chapters 5 and 6.

Documents techniques by which user satisfaction may be measured in completed buildings.

Shafer, Elwood L. Jr .. "The Photo·Choice Method for Recreation Research", U. S. Forest Service Research Paper NE-29,1964.

Van Ireland, Jr., J., "Two Thousand Dutch Office Workers Evaluate Lighting", Research I nstitute for Public Health Engineering, Report No. 39, Delft, Netherlands, June, 1967.

Lau, J., "Report of a Preliminary Experiment on the Validity of the Use of Models in Subjective Lighting Assignments," University of Strathclyde, August, 1968.

Spivak, M .. "Some Psychological Implications of Mental Health Center Architecture", a paper delivered at the New England Psychological Association, Boston, November, 1966.

Kahn, I.R .. "The Influence of Color and Illumination on the Interpretation of Emotions", thesis submitted to

Psychology Department faculty, University of Utah, August, 1967.

BIBLIOGRAPHY

Wools, R .M., "Some Experiments in Arch itecture - A Brief interim summary of a research project into the effects of the physical environment on behavior", September, 1968.

4. Built environment

Bu ilding Research Station, "Integrated Daylight and Artificial Light in Buildings", Building Research Station, Garston, Herts., England, November 1966.

Markus, Thomas A. (tech . ed.), "Progress in Daylighting Design", Light and Lighting, Vol. 56, 1963.

5. Design process

Hewitt, H .. John Kay, J, Longmore and E. Rowlands, "Oesigning for Quality in Lighting", Ill um inat ing Engineering Society (London), paper presented at Harrogate, England 16 -1 8 May, 1966.

Manning, Peter, "Systematic Design Methods and the Building Process", The Architects' Journal I nformation Library, 22 September, 1965.

Markus, Thomas A., "The Role of Building Performance Measurement and Appraisal in Design Method", The Architects' Journal Information Library , December 20, 1967.

Studer , Raymond G., "On Environmental Programming," The Architectural Association Journal, Lo ndon, May 1966, pp. 290-296.

Wa ldram, J.M., "Design of the Visual Field", Transactions of the Illuminating Engineering Society (London), Vol. 23, Nov. 2, 1958 , pp. 11 3-23.

Planning for Davlight and Sunlight, Planning Bu lletin 5, Min istry of Housing and Local Government, London: Her Ma jesty's Stationery Office, 1966.

Halldane, J. F., "Human Factors in Light ing Design", I.E.s. Lecture, February, 1968.

Canter, O.V ., "The Need for a Theory of Function in A rchitecture" , University of StrathcJyde, March, 1968.

6. Visual environment criteria

Fischer, Robert E. (Ed), Architectural Engineering, Environmental Control, McGraw-Hi li, New York, 1964, pp. 11 8- 164: Lam, William M.C .. "Lighting for Architecture."

112

BIBLIOGRAPHY

Lam, Wi lliam M.C., "The Lighting of Cities", Architectural Record, June and July, 1965.

University of Michigan, School of Environmenta l Research, Architectural Research Laboratory, "SER 1,2,3,4, Environmental Abstracts", University of Michigan, Ann Arbor.

This is an attempt to abstract. evaluate. and analyze current literature on environmen t design. Well-conceived, but incomplete.

Cuttle, C .. Valentine, W.B., Lyres, A., and Burt, W .. "Beyond the Working Plane" , p. 67 .12, C.I.E ., Washington, 1967.

'Turner, D.P.Ed .. WINDOWS A ND ENVIRONMENT, Pilkington Environmental Advisory Serv ice, McCorquodale & Co . Ltd .. 1969.

7. Lighting criteria

Hopkinson, R. C., Architec tural Physics: Lighting, Her Majesty's Stationery Office, London, 1963.

Puts lighting research in proper perspective. Scientific support for most architects' point of view about reason­ab le l ight levels and consideration of day light.

'Hopkinson, R.G. and Kay, J.D ., The Lighting of Buildings, Frederick A. Praeger, New York , 1969.

Weston, H.C., Light, Sigh t, and Work, Medica l Research Council of Great Britain, H. K. Lewis & Co., Ltd., (pub.) London, 1962.

8. Multi-varient research methods

Manning. Peter, "Lighting in Relation to Other Components of the Total Environment", a paper presented at the Illum­inati ng Eng ineering Society Nat iona l lighting Conference, Churchi ll Co l lege, Cambridge, England, 25-27 March, 1968.

Manning, Peter, "Multi-D isciplinary Research for Architecture", The A rchitects' Journal Information L ibrary, 15 November, 1967.

Horowitz, Harold, "An Introduction to Research Methods for Architecture", AlA Journal , January, 1964, pp. 62-66.

9. Cost studies

Loudon, A. G. (Bui lding Research Stat ion), "Window Design Criteria to Avoid Overheating by Excessive Solar Heat Gains", Current Papers 4/68, February, 1968.

113

BIBLIOGRAPHY

Northern Illinois Gas Company, "Analysis of lighting Load Effect on Cooling Requirements", paper presented at American

Gas Associat ion , Inc .. Research, Utilization and Market ing

Conference, Chicago, June, 1966.

Tregenza, P. R. , "A Study of the Relationship Between the Design Level of Illumination and the Cost of Lighting", Building Science, Vol. 2, No.1, March, 1967.

10. Materials and engineering data

Griffith, James W., Predicting Daylight as Interior Illumination, Libbey-Owens-Ford Glass Company, 1958.

Gives all factors necessary for ca lcu lat ing daylight levels.

11. Task analysis

Bechtel, Robert B. (The Environmental Research Station, Topeka, Kansas). "Hodometer Research in Architecture", Milieu, the Environmental Research Foundation News

Report, Ser. 2, Vol. 1, April, 1967.

Chorlton, J. M., Frequency and Duration of School Visual Tasks, Illum inating Engineering Research Insti tute,

Progress Report No.3, 4 April. 1960.

12. Vision research

Blackwell , H. R., " Development and Use of a Quantitative Method for Specification of Interior Illumination Levels

on the Basis of Performance Data", Illuminating Engineer­ing, New York, 54, pp. 317-353.

Blackwell, H. R., "The Evaluation of Interior Lighting on the Basis of Visual Criteria", Applied Optics, September, 1967.

Blackwel l , H. R., "A General Quantitative Method for Eval­uating the Visual Significance of Reflected Glare, Utiliz-ing V isual Performance Data" , paper No. 50-8, presented at

the National T echnical Conference of the Illuminating

Engineering Society, St. Louis, Missouri , September , 196 1.

Blackwell , H. R., R. N. Schwab, and B. S. Pritchard, "Visibility and Illuminat ion Variables in Roadway Visual

Tasks",lIluminating Engineering, Vol. L1 X, No.5, May, 1964.

Boynton, Robert M. and N. M iller, "Visual Performance Under

Conditions of Transient Adaptation", Illuminating Engineering, Vo l. LVIII , NO.8, August, 1968.

114

BIBLIOGRAPHY

Charlton, J. M., "Part II - Field Measurements of Loss of Contrast", Illuminating Engineering, Vol. lIV, No.8, August, 1959.

Fry, Glenn A" "Assessment of V isual Performance", Illuminating Engineering, Vol. LVII, No.6, June, 1962.

Griffith, James W., "Analysis of Reflected Glare and Visual Effect from Windows", Illuminating Engineering, March, 1962.

Griffith, James W., "Vei l ing Reflection Studies with Side­wa ll Lighting", Illuminating Engineering, May, 1966.

Documents advantages of side lighting vs. overhead lighting.

Hopkinson, R. G. and W. H. Atkinson, "A Study of Glare from Very Large Sources", paper presented before the Illuminating Engineering Society, Detroit, 10 September, 1960.

Eastman, Arthur A" "Color Contrast vs. Luminance Contrast", a paper presented at the National Technical Conference of the I.E.S., Phoenix, September, 1968.

Taylor, N. W., "New Light on Visual Threshold Contrast", Illuminating Engineering, Vol. LVII, No.3, March, 1962.

"Present Status of Veiling Reflections Know-How", a progress report of the Veiling Ref lections Subcommittee of the ROO Comm ittee, Illuminating Engineering, pages 433-435, August, 1968.

Hopkinson, R. G" "Dayl igh t as a Cause of Glare", Building Research Station, Current Papers, Design Series 27.

Hi ll , A. R., "The Sensory Scaling of Ease of Seeing Through a Mesh" Department of Architecture, University of Strathclyde, October , 1968.

Hill, A. R., "A Psychophysical Scale of Visibility", based on a paper del ivered to the Research Symposium on Visual Psychophysics Neurology held at City University, May, 1968.

13. Eye movements

115

Hebbard, Frederick W" "Micro Eye Movements: Effects of Target Illumination and Contrast", Final Report of Illuminating Engineer­ing Research Institute Project, No. 71-8.

Mackworth, Norman H. and Anthony J. Morandi, "The Gaze Selects Specific Features with in Pictures". Perception and Psychophysics, January, 1967.

Mackworth, Norman H., "A Stand Camera for Line-of-Sight-Record ing", Perception and Psychophysics, Vol. 2, Psychonomic Press, Goleta. Cali fornia, 1967.

Thomas, E. Llewellyn, "Movements of the Eye", Scientific American,

Vol. 219, No.2, August, 1968.

BIBLIOGRAPHY

14,

I 15,

116

Mackworth, N.H" "Some Suggested Uses for the Optiscan - A Head~Molillted Eye Camera", American Society of Mechani ca l Eng ineers,

~'"per No. GO-WA-304, 1960.

Mackworth, N. H. and Thomas, E. L., "A Head Mount ed Camera", June, 1961.

""Bakan, Paul, Ed., Attention, D. Van Nostrand Co., Inc., Princeton, New Jersey, 1966.

Communications theory

""Broadbent, D. E., Perception and Communication, Pergamon Press, 1958.

Perceptual Psychology

Bernard, Eugene E., Biological Proto types and Synthetic Systems, Vol. 1, Plenum Press, New York, 1962.

Gombrich, E. H., A rt and Illusion, a Study in the Psychology of Pictorial Representation, A. W. Mellon Lectures in the Fine Arts, 1956. National Ga llery of A rt, Washington , D. C., Bol li ngen Foundation, New York

Gregory, R. L., Eye and Brain, the Psychology of Seeing, World Un iversity Library, McG raw-H ili Book Co., 1966

Halldane, John F., Architecture and Visual Perception,

Department of Architecture, University of California Berkeley, 1968.

Halldane, John F., Psycholophysical Synthesis of Environmental Systems, Ca li fornia Book Co., Ltd., Berke ley, Cali forn ia, 1968.

Hering, Ewald, Outlines of a Theory of the Light Sense, Harvard University Press, Cambridge, Massachusetts, 1964.

""Hesselgren, Sven, The Language of Architecture, Student­litteratur , Lund, Sweden , 1967 .

Hockberg, Ju lian E., Perception, Prenti ce-Hall , Inc. Englewood Cl iffs, New Jersey, 1964.

*Hu rvich, Leo M. and Dorothea Jameson, T he Perception of

Brightness and Darkness, A llyn and Bacon, Inc., Boston, 1966.

Hay, Peter, "Visual Perception and Apparent Brightness", unpublished paper.

I tte lson, William H., V isual Space Perception, Sp ri nger, New York, 1960.

Marek, Julius, " Inforrnation, Percept ion and Social Context, 1 _

Sirnple Level of Perceptual Response", Human Relations, 15, 1962. PI'. 17-25.

BIBLIOGRAPHY

117

Marek, Ju lius, "Information , Perception and Social Context, 2 -The Balance and Relevance of Complex Perceptual Responses" Human Relations. 19.1966. pp. 353-380.

Ne isser, Ulric, "The Processes of Vis ion", Scientific American, Vo l. 2 19. No. 3. September . 1968.

Sokolov. Ye.N.. Perception and the Conditioned Reflex, Pergamon Press. the MacMili3n Co .. N. Y .. 1963

St ipe, Robert E., "Percept ion and Environment: Foundations of Urban Design", proceedings of a 1962 Sem inar on Urban Design, Institute of GovernlTient, University of North Carol ina,

Chapel H ill. January 1966.

Vernon, M. D. (Ed.) , Experiments in Visual Perception, Pengu in Books. 1966.

Wapner, S., "An Organismic - Developl1")ental Approach to the Study of Perceptual and Other Cognitive Operations", reprinted from Cognition: Theory , Research, Promise by Constance Scheerer Harper and Row, New York, Evanston, and London, 1964.

Wapner . S .. McFarland. JH .. and Werner. H .. "Effect of Visual Spatial Context on Perception of One's Own Body", British Journal of Psychology, 54. 1. pages 41-49.1962.

Lau. J .. "A Semantic Study of the Concep t of G loom in Lighting". University of Strathclyde. Apr il. 1967.

Acking. C. A .• Translation of a Prelim inary Research Report 20. 12.67 concerning Visual Perception of Environment (for internal use only ). Lund Institute of Technology, Lund, Sweden.

Ho lmberg, L .. Ku ller R., and Tidblom. 1 .. "The Perception of Vo lume Content of Rectangu lar Rooms as a Function of the Ratio Between Depth and Width" , Psychological Research Bulletin, Vo l. 1. 1966, Lund University, Sweden.

Holmberg, L., Kuller . R., and Tidbl om, 1 ,"Stab ility of Individual and Group Data in the Percept ion of Volume Content of Rectangular Rooms as Measured bV a Production and an Esti mation Method," Psychological Research Bulletin, Volume 7,1966, Lund University, Sweden.

Holmberg , L. , Almgren, S .. Soderpalrn, A. C .. and Kuller. R .. "The Perception of Volume Content of Rectangular Rooms - Comparison Between Model and Fu ll Scale Experirnents", Psychological Research Bulletin, Volume 11 , 1967, Lund Univers ity, Sweden.

*Gibson, James J., The Senses Considered as Perceptual Systems, Houghton M ifflin Company. Boston, 1966.

Gibson, James J., Perception of the Visual World.

BIBLIOGRAPHY

'Mueller, Rudolph, and the Editors of Life, Light and Vision, Life Science Library, Time Incorporated, New York, 1966.

*N eisser, U lric, Cognitive Psychology, Meredith Publishing Co. New York , 1967.

*Warr, Peter B. and Knapper, Christopher, The Perception of People and Events, John Wiley & Sons, London, 1968.

16. Color perception

Black, J. Courtney, "Meaning of Color", Master's Thesis, University of Utah, Salt Lake City, Utah.

Ca mpbell, Joh n B., "Color Vision .. the Land Ex peri ments", Astounding Science, Fact and Fiction, Vol. 64, 1960.

Land, Edwin H. "Experiments in Color Vision", Scientific American, May, 1969.

Land, Edwin H., "The Retinex", American Scientist, 52, 1964.

Land, Edwin H., "'Color Vision and the Natural Image, Part 1 and Part 11, Physics, Vol. 45, 1959.

Walls, Gordon L., "Landi Landi" PsVchological Bulletin, Vol. 57, No.1, 1960.

Swedish Colour Foundation (Anders Hard), "A New Colour Atlas Based on the Natural Co lor System by Hering·Johansson," Swedish Center Colour Foundation, Stockholm, 1965.

Swedish Colour Foundation, "Attributes of Colour Perception", Swedish Colour Center Foundation, Stockho lm, 1967.

Yilmaz, Huseyin and Lewis C. Clapp, "Perception,: International Science and Technology, Conover·Mast, New York, 1963.

A contemporary color theory explaining the complexity of "What is the right color of light'''

Helson, Harry, Illuminating Engineering Research Institute Annual Report, 1965, pp. 6-14.

Birren, Faber, Light, Color and Environment, Van Nostrand Reinhold Company, New York 1965.

17. Performance and fatigue

118

Cook, Desmond L., "The Hawthorne Effect in Educational Research, "Phi Delta Kappan, December, 1962.

Every architect should be familiar with the Hawthorne

BIBLIOGRAPHY

experiments, w hich showed that "a direct relationship between illumination and production was nonexistent".

Khek, J. and J. Krivohlavy, "Variati on of Incidence of Error w ith Visual Task Difficu lty", Light and Lighting, May , 1966.

This documents what cou ld prove to be a very important theory. showing increase of fatigue due to excessive lighting.

Stone, P. T., " Ergonomics of the Env ironment". paper presented at IES National Light ing Conference, Churchill College, Cambridge, England , March 25-27, 1968.

Claimed performance increases in trade journals document­ing new lighting installations.

18. Stress-sensory deprivation

Carson , 0., "An Environmental Approach to Human Stress and Well Being : with Implications for Planning". Mental Health Research Inst itute Reprint 1944, Ann Arbor, Michigan.

Myers, Thomas I., "Tolerance for Sensory and Perceptual Deprivation", Chapte r in Sensory Deprivation: Fifteen Years of Research, edi ted by J. P. Zubek, App leton­Century-C rofts, New York, 1967.

19. Acoustical and thermal environment

Bolt, R. H .. K. N. Stevens and W. A. Rosenblith, "A Community's Reaction to Noise: Can it Be Forecast?" Noise Control, Vol. 1, No.1, January, 1955, pp. 63-71.

20. Visual environment

Best, Gordon A., "D irection Find ing in Large Buildings", dissertation, Universi ty of Manchester, Institute of Science and Technology, Manchester, Eng land , 1967 .

Birren, Faber and Henry L. Logan, " The Agreeable Environment",

Progressive Architecture, August, 1960.

Bodman, H. W./ "Quality of Interior Lighting Based on Luminance", Transactions of the Illumination Engineering Society, (London),

Vol. 32, No.1, 1967,

Co l lins, Wendy M., "The Determination of the Minimum Identifiable Glare Sensation Interval Using a Pair­Comparison Method" I Department of Scientific and Industrial Research, Building Research Station, Note No. E 1172-February, 1962.

119

BIBLIOGRAPHY

Hardy, A, c., "The Colour Co-ordination of Ti le and Other Factory Coloured Products of the Building Industry in Relation to BS2660", The Co lour Group, 1965.

Hardy, A. C., "Colour in Landscape", I nternational Conference Keele University, July, 1965.

Hardy, A. C., "Insultation and Fenestration", Electricity, July/August, 1967, pp. 268-270.

Hardy, A . C. , "Space Perception and Externa l Enclosu re"

Hopkinson, R, G, and W. M. Collins, "An Experimental Study of the Glare from a Lumi nous Ceiling", Department of Science and Industrial Research, Building Research Station, Note No. E1275.

Manning, Peter, "Windows, Environment and Peop le", Interbuild/ Arena, OctOber, 1967.

Markus, ThomasA. and Adrian R, Hi ll , "Some Factors Influenc­ing Vision Through Meshes", unpublished paper, Un iversi ty of Strathclyde, Glasgow, Scotl and,

Page, J. K., "The Role of L ighting in the Search for Better I nteriors--Some Problems" , Illuminating Engineering Society (London), Vo l. 27, No, 4,1962.

"Proceedings of Initial Meeting Estab lishing CIE Study Comm ittee on Psychology in the Visua l Environment", Sven Hesselgren, Chairman, StockhOlm, 1968.

Wohlwil l , Joachim F, " The Physica l Environment: A Problem for a Psychology of Stimulation", The JOllrnal of Social Issues,

Vol. XX I I, No.4, pp . 29-38, 1966.

Jay, Peter, "Visual Perception and Apparent Br ightness", unpublished paper, London, 19 October, 1967.

Performance Criteria for the Luminous Environment, pp. 20-36, [See 7006J .

Markus, T. A., "T he Function of Windows--A Reappraisa l", Building Science, Vol. 2, pp, 97- 1 21, Pergamon Press, Great Britain, 1967 .

Cullen, Gordon, TOWNSCAPE, Reinhold Publish ing Corporation, New York, 1961.

21. Environmental psychology

120

Canter, David V., "Office Sile, An Example of Psychological

Research in Architecture" , The Architects Journal Information Library, 24 Ap ril , 1968.

BIBLIOGRAPHY

Wapner, Sey mour and Heinz Werner, "Changes in Psychologica! Distance Under Condit ions of Oanger", Journal of Personality, Vol. 24, No.2, December, 1955.

Lynch, Kevin, The Image o f the City, The Technology Press & Harvard University Press , Cambridge, Massachusetts, 1960.

22. Behavioral science

Gutnam, Ro bert, "The Questi ons Arch itects Ask" Transactions of the Bartlett Society, Vol. 4, 1965-66.

Altman, Irwin, "The Effects of Social Isolation and Group Composition on Perform ance" Human Relations, Vol. 20, No.4,

1967, pp_ 313-340.

Studer, Raymond G. and D. Stea, "Archi tectural Programming and Human Behavior", Journal of Social Issues, 22,4 Oct., 1966_

Roeth lisberger, F. J. and Dickson, W. J., Management and the Worker, Harvard University Press. Cambridge, Massachusetts, 1966.

23, Anthropology

Hal l, E. T., Hidden Dimensions, Doubleday, 1966.

Hall, E. T., The Silent Language, Fawcett Publications, Inc. Greenwich, Conn., 1959

Meade, Margaret, Conference Procedures, Columbia University Alumni News

Jacobs, Jane, Life and Death of American Cities.

24_ Public health and saf ety - ophthalmology

121

Cogan, David, M.D., "Popu lar Misconceptions Pertaining

to Ophthalmo logy" , N. E. Journal of Medicine, Vol. 24,1941

pp. 462-466.

The Director of ophthalmology at the Massachusetts Eye and Ear Infi rmary presents the medical analysis of illumination

levels.

Spivack, M ayer, "Sensory Distortions in Tunnels and Corridors",

Hospital and Community Psychiatry, American Psychiatric

Associat ion, January, 1967.

Cogan, David, "Damage to Rats' Eyes for Continuous Exposure

to Light", Stenographic Record, seminar sponsored by The

State University Construction Fund, State University of

New York, at Saratoga Springs, N.Y., July 6-7, 1967.

BIBLIOGRAPHYI

25. Educations methods

Demos, George D., "Contro lled Physical Classroom Environments and Their Effects Upon Elementary Schoo l Ch ildren (Windowless

. Classroom Study)", Research Project by the Off ice of River· side County Superintendent of Schools. Riverside. Californ ia

Manning, Peter, "An Experimental Study to Seek More Effective Communica tion to Architects of the Resu lts of Bu i lding Research", Institute of Advanced Architectu ral Studies.

26. Research programs, organization summaries, bibliographies, indexes

122

Annual Report, Illuminating Engineering Research Institu te, 196 1,1962,1963,1965,345 East 47th St., New York 17, NY

Evans, Benjamin H" AlA Research Survey, the Ameri can Institute of Arch itects, 1735 New York Avenue, NW, Washington, D. C.

Hopkinson, R. G .. "Environmental Research and Bui lding Pract ice", Light and Lighting, July, 1968

Report of the Illu m inati ng Engineeri ng Research Institute Symposium on Light and Vision Research , at So ester berg , 14· 16 June, 1965.

Research Bu lletin 1, University of Strathclyde, Department of Architecture and Bui lding Science, September, 1968.

List of Published Social Survey Repor ts, The Government Social Survey, Atlantic House, London, 1968.

Underlying all d iscussions was the recognition of the important

role of total environment in determining effective lighting criteria.

Especially noteworthy was the emphasis everyone placed on humanistic elements of perception, such as proper rendition of

color; acquisition of meaningful information; avoidance of discom­

fort, distraction and gloom; and creation of a comfortable, pleas­ing environment. Not iceably de-emphasized by the part icipants

were mechanistic factors -- footcandle tables, brightness ratio, scisso rs curve, etc.

The specialists as well as the generalists agreed that many problems in lighti ng design cannot be met simply by applying a number or

even a set of numbers. The designer and the architect often face

situations which are not clear-cut, not strictly black or white, therefore must base many of their final decisions on their own

va lue judgements. The participants further agreed that any set of

criteria for light ing design, to be of real value, must offer guide­

lines upon which these judgements can be f irmly based.

concluded that Dr. Ralph Hopkinson's formula as presented in the British I lluminating Engineering Society (I ES) Code offers a better approach. (See Appendix F of this report.)

Finally, everyone (i ncluding the architects) agreed that in cu rren t practice the architect too often does not become sufficiently in­volved with decisions on lighting design. The consensu s of the con­ference was that the architect has the right general background f or this responsibility and that he mu st become more involved . To aid him in this resp onsibility, performance criteria must be written in terms meani ngful and useful to him. It was agreed that the f ina l report should be written w ith that approach in mind .

•••••••• Conference Participants ••••••••••••••••••••••••••••••

State University Construction Fund

State University of New York

Educational Facilities Laboratories, Inc.

M. I. T. Project Group Leaders

126

Richard G. Jacques

Director of Research and Development

Wi lliam C. Sawyer

Research Associate, Project Coordinator

Rima E. Bostick

Research Consultant

Morton Gassman

Assistant Vice Chancellor for Facilities Programming & Research Office of

Architecture & Facilities

Thomas Dav is Assistant for Facilities Research, Department of Architecture & Facilities

Jonathan King

Vice-President and T reasurer

Dr. AlbertG. H. Dietz Professor of Building Engineering at M.I.T. Director of the Project. Past direc­tor of Building Research Institute; past Director of American Society for Test­ing and Material s; past Chairman Building Research Advisory Board ; Materials

Advisory Board Committees for Department of Defense.

Many current guidelines disavowed

Present analysis techniques challenged

125

1. Low levels of illumination cause organic harm to the eyes. This was rejected. Medical evidence does not substantiate t he claim. Poor illumination causes no more organic harm to t he eyes than indistinct sound damages the ears.

2. The footcandle is the best criterion for determining the proper illumination of a space. (Agreement was unanimous that) this standard is inadequate. The conferees recommended that a performance index be developed that would consider quality of lighting as well as quantity

3. Increasing the level of light intensity is the only way to im­prove visual performance. Increasing intensity will result in improvement only when all other factors remain constant. Even then, large increments are necessary to produce small degrees of improvement. Quality, not quant ity, is the key . A small improvement in the quality of the luminous environ­ment will produce a much greater degree of improvement in performance than will a large increase in intensity.

4. Rooms with uniform task distribution require uniform light­

ing. Adoption of a single cut-off value for the total area of a room ignores the fact that visibility is often satisfactory over a wide ra nge of illumination. Since value judgements are used in creating criteria, the conferees pointed out that if 70 to 80 percent of the area meets the required criteria the lighting is likely to be satisfactory.

5. Uniform lighting is desirable even in rooms with non-uniform task distribution. The participants disagreed marked ly with this genera lization; they proposed instead a moderate level of high-quality room lighting, suitable for most tasks, augmented by local lighting for the performance of unusally difficult or specialized tasks.

The present technique of identifying the most diff icult visual task to be p~rformed in a room and then specify ing the total lighting design based on this tas k was labeled as ineffective and inefficient. Often the most difficult task is performed only 5 percent or less of the time the room is be ing used; to design the total room lighting specifically to meet tha t five percent would be unrealistic and costly. Instead, all tasks should be identified at the outset and the percentages of times used should be analyzed. Total room lighting should not be designed for the most difficult task unless it is un­questionably the most predominant task. Additional light can be

suppl ied as needed.

Another technique that came under fire was the American system for determining direct glare discomfort in lighting. The conferences

Specialists

127

Robert J. Pelletier Research Associate, Department of Architecture, M.I.T. Extensive experience in hospital design and research, and other phases of research in design and construction.

Professor Robert Rathbone Department of Humanities, Project Editor

William M. C. Lam Lighting Consultant, William M.e. Lam & Associates. Primary consultant to M.I.T. for this project. Extensive experience in coordinating lighting and architecture. Projects have included a broad range: schools, cultural centers, office buildings, hospitals, streets, campuses.

Dr. H. Richard Blackwell Director, Institute for Research in Vision, Ohio State University. His findings form the basis of current U.S. lighting criteria.

Dr. Robert M. Boynton Professor of Psychology, Director of Center for Visual Science at University of Rochester.

John M. Chorlton Headed the committee responsible for the 1962 American Standard Guide for School lighting. Chairman of Education Committee, IES; member College lighting Committee.

Dr. David Cogan Chief of Ophthalmology, Massachusetts Eye and Ear Infirmary, Boston, Mass. Henry Willard Williams Professor of Ophthalmology, Harvard University.

Or. James J. Gibson Professor of Psychology at Cornell. Author of "Perception of the Visual World" and "The Senses Considered as Perceptual Systems."

James W. Griffith Chairman, Department of I ndustrial Engineering, Southern Methodist Univer­sity. Authority of Daylighting; U. S. Delegate to numerous international meet­

ings on the subject. Vice-President, IES.

Dr. R. G. Hopkinson Professor of Environmental Design and Engineering, University College, London. Studies on glare adopted by IES of Great Britain_ Research on light­ing formed basis of building regulations issued by Government Education Authorities. Formerly in charge of the lighting work at the Building Research Station, England; Past Pres. IES, Great Britain.

Peter Manning Founded and directed Pilkington Research Unit at University of Liverpool, a mUlti-disciplinary team investigating the "total environment" within build­ings. Editor of "Office design: a study of environment" and other reports.

Generalists

128

Thomas Markus

Professor of Building Science, University of Strathclyde, Glasgow. Studies in use of glass and windows. Research in environmenta l problems. Established lighting research department at Pilkington Brothers Glass Co. Author of "The Function of Windows - A reappraisal".

Foster K. Sampson Consulting engineer in all phases of electrical design, including schools and

universities. Member, comm ittee responsible for the 1962 Amer ican Standard Guide for School Lighting.

J. M. Waldram Consu lting lighting engineer (England): daylight, street lighting, problems of

seeing and visibi lity. new methods of interior l ighting; Past President, IES of Great Britain .

Dr. Brian W. P. Wells Professor of Psychology, clinica l psycholog ist. Concerned w ith problems of

architectural psychology; member of Pilkington Research Unit.

John Hancock Callender Professor of Design and Co nstruct ion, Pratt Inst itute. Director of demonstra­tion project to reduce cost of high-rise and low-income housing.

Ranger Farrell Architect. Acoustical- l ighting consultant to numerous educational construc­

tion projects.

George Hutchinson Architect, partner, Perkins and Will , Ch icago. Many projects in the area of higher education: University of Denver, Utica College, Knox Col lege, Concor ­dia Teachers Col lege. Chicago Housing Authority_ Federal Housing Adminis­

tration . Chicago Planning Commission.

Alexander Kouzmanoff

Architect and Professor. Victor Christ-Janer Associates. Current ly developing Nassau College for S.U .C.F .

G. Theodore Larson Professor. Director of School Environments Research Project , University of Michigan. Current study: the effects of environment on t he learning process.

Bernard Rubin

Electrical Consulting Engineer. Formerly design eng ineer for the Hydro- Elec­tric Power Commission of Ontario.

Bernard Spring Professor. Senior Research Architect and Lecturer at School of Architecture, Princeton University: Technology of Environmental Control. Co-director, A l A Research in Education, Princeton University.

Peter Tirion Architect. Full-time staff member of the Metropo li tan Toronto Schoo l Board's Study of Educational Facilities.

After the two days of conference Messrs. Dietz, DeMartino, Lam and Markus met to review the extens ive discussions and decide how they should affect the final document. They concluded that:

1

2

Recognizing that weighting of the activities, needs, and ability of the visua l environment to provide for those needs were not accurately quantifiable, it was decided not to fur­nish check lists as proposed at Skidmore but instead that SUCF could best ach ieve its objectives by controlling the entire lighting design process (see Part II - L ighting Design Practice), and that:

a. The needs, priorities, and environmental character istics be listed in an open-end fash ion so they would be revised by designers for the ir specif ic projects and by the SUCF on the basis of user surveys (see Chapter 5).

b. A type of "light budgeti ng" system be developed that would have some control of performance, but recognize and encourage log ica l va lue judgements (see Chapter 6).

c. SUCF require a logical design process that would insure consideration of the relevant factors and partic ipation in "transparent" decisions by all parties -- architect (design­

er), the Fund, and user (see Chapter 7)

The so-called "psych ological" factors were deemed of suf­ficient importance to be given substantial weight in the per­formance criteria. It was suggested the pr inciples be presented even though they were not yet quantifiable. (See Part I -Lighting Design Pri nciples.)

131

Participants

Dr. Albert G. H. Dietz Head of M.I.T. Project Group

Wi lliam M. C. Lam Consultant, M.I.T. Project Group

Lawrence A. DeMartino State University Construction Fund

Dr. R. G. Hopkinson University College, London

Dr. H. Richard Blackwell Director, Institute for Research in Vision, Ohio State University

James W. Griffith

Chairman, Department of Industrial Engineering, Southern Methodist University

Thomas Markus Professor of Building Science, University of Strathclyde, Glasgow

3

4

The Visua l Performance Index (VPI) proposed by Blackwell at the Skidmore Conference was not yet sufficiently develop­ed to be used as an exact performance cri terion for penci l handwri ting, nor was the visibility of pencil handwri t ing considered the dominant determinant of total performance of the visual environment. However the work appeared im­portant and valid as far as it went, and thus current develop­ments shou ld be included in the report in a format most use­ful for aiding value judgement of one of the aspects of visual environment.

It was decided that, while Equivalent Spherica l Illumination Es wou ld be the most convenient unit for engineering pur­poses, that the corresponding values of Relative Contrast Sen­sitivity (RCS) would give more realistic impressions for com­parison of alternate I ighting systems. Thus the data would be presented for computing ESI from actual illumination levels (measu red and computed ), and also a chart for converting Es to RCS.

Hopkinson's Discomfort-Glare Formula appeared to be rele­vant only to regular arrangements of " meaningless" light fixtures (t hose that are not a positive contribution to biologi­cal needs), and thus not usefu l for evaluat ion of w indows or the best forms of art ificia l illumination (that may not use regular arrangements of distracting "meaningless" light fix­tures). Therefore, while no limiting glare index could be listed, the fo rmula was considered useful (w ithin its limits) as a help­fu I reference.

2l c: t Q) :;: Q)

~~--~--~~-------------------------------------~-----­Typical specular materials

Lum ina ire reflector materials:

Building materials:

Typical diffusing materials

Luminaire reflector materials:

Masonry and structural materials:

Wood:

Paint:

Silver Chromium Aluminum: Polished

A lzak po l ished Sta i n less stee I

Clear glass or plastic

Stainless steel

White paint White porcelain enamel

White plaster Wh ite te rra-cotta White porcelain enamel Limestone

Sandstone Marble Gray cement Granite Brick : Red

Ligh t buff Dark buff

Light birch L ight oak Dark oak Mahogany Wal nut

New white paint Old whi te paint

90-92% 63-66% 60-70% 75-85% 50-60%

8-10% 50-60%

70-90% 60-83%

90-92% 65-80% 60-83% 35-60% 20-40% 30-70010 20-30% 20-25% 10-20% 40-45% 35-40%

35-50% 25-35% 10- 15% 6-12% 5-10%

75- 90% 50-70%

From: Flynn, John E. and Segi l, Arthur W. Archirecturallnterior Systems (Van Nostrand Re inhold Co., New York: 1970), p . 126.

133

1 2

3

4 5

6 7 8 9 10

From

135

We see better the more light we have, up to a point, but this light must be free from glare.

We see better if the main visual task is distinguished from its surroundings by being brighter, or more contrasting, or more colourfu l, or al l three. It is therefore importan t to identify the main focal points and build up the lighting from their require­ments.

We see better if t he things we have to look at are seen in an unobtrusive and unconfusing setting, neither so br ight nor so

colourful tha t it attracts the attention away, nor so dark that work appears excessively bright with the result that the eyes are riveted on to the visual task . Good lighting therefore pro­vides a moderate and comfortable level of general lighting, with preferential lighting on the work. This can be called foeallighting.

The surroundings should be moderately bright, and this should be achieved by combination of lighting and decora­tion.

No source of light should be a source of glare discomfort. Ex­cessively bright areas should never be visible. Windows should be provided with curtains, blinds or louvres to be brought in­to use when the sky is very bright.

Plenty of light should reach the ceiling, in crder to dispel any feeling of gloom, and to reduce glare .

Sources of light shou ld be chosen to ensure that the colour rendering which they give is satisfactory for the situat ion in which they will be found.

Care should be taken to eliminate any discomfort from flick­ering light sources.

A dull uniformity should at all costs be avoided. Small bril­liant points of light can give sparkle to a scene without caus­ing glare.

The lighting of a building should be considered always in re­lation to its design and in particular to the scheme of decora­tion to be installed. On no account should lighting be con­sidered to be merely a matter of windows or fittings. The whole environment enters into a good light ing installation .

"Some Principles of Good Lighting" from Arch itectural Physics: lighting by R. G. Hopkinson (Her Majesty's Stationery Office, London, 1963. Page 125).

SPACE PROGRAM CHART SPACE

BIOLOGICAL AND ACTIVITY NEEDS

a d >-BIOLOGICAL NEEDS l- e VISUAL SUB·ACTIVITIES -cc a cc c..

Movement Circulation information Relaxation - Stimulation Physical Dangers

Orientation in space enclosure time weather

Restful visual activity of interest non-activity

No distraction by high signal-noise ratio upsetting constancies upsetting expectations

b ACTIVITY NEEDS C PARTI- f VISUAL 9 EVENTS AND CIPANTS OBJECTIVES SUB-ACTIVITIES

Looking at:

BEHAVIORAL 1. __________________ _ 4. ______________ __ WHEN USED: LIGHTING BUDGET

TYPE: OBJECTIVES 2. _____________ _ 5. _______________ __ Day __ %

Night __ % 3. ___________________ __ 6. ______________ __

INFORMATION NEEDS HARDWARE SYSTEM

k INFORMATION NEEDS 0 CHARACTERISTICS OF VISUAL ENVIRONMENT

Routes, signs, layouts of objects and Positive, clear articulation of paths, nodes and areas by building

building elements elements and graphics Adequate illumination, shadows, gradients: minimum disability Levels, edges, obstacles, people, and other

moving objects glare, irrelevant disturbing pattern

Shape of space; relation to exterior Spatial and structural articulation

Nature of enclosing structure Clear windows, skylights Daylight reference No glaring light fixtures; relevant order of focus for activity View of sky, winds, rain, sunlight, artwork, and characteristics of space

and other people No mixed color sources on similar surfaces in similar Isolation when desired circumstances No disturbing color Illuminated wall and ceiling surfaces during the day to balance

Expected relationship of brightness: window brightness and to relate to exterior daytime

interior surfaces to exterior conditions

PROJECT

U

h i LOCATION j REMARKS I OBJECT m INFORM. NEEDS n NEG. P PRIME LIGHT SOURCE CHARACTERISTICS t REMARKS FACTORS

HOR. VERT. CHAR. Color q POSITION RELATIVE r S WAVE CHAR. >- SIZE y To surface To viewer

>- <0 I:: I-

y C1> I:: Cl ~ ... '" "0 E E .. ~ '" <0 :e '"

or- :l: <0 cc ... ... I:! 0. X

.Cl <0 .. Cl o ., N ::; ::; .. () ::; ... <0 0 ... - ...

a -;;; '" .. <0 E '" E~ .~~ .;: ... "' ... <0 ~ '::; ::; ., .... ... "0 N- X - y c: () r: r: ... I:: I:: ",Cl ... Cl .~ ]' c '" -Y .- ()

;;: 0 8 .e '" "" Q) '" -<0 ~ '"

~~ 0 '" 0 <0 <0 ~ ~ I:! .... 0 "".e ... r: o r: .- r: co ~

(5 ::;0. ....I <!l ....I <!l 2D 3D cc II. « I- a U Uti) <!l« 2« >« :a:<c :a: c.. II.tI) rao.

c..tI)

FOOTNOTES NUMERICAL CRITERIA

Unit of <0 .::;

Measure 0"_ <0 "" cc>

SPACE PROG RAM CHART SPACE TYPICAL BEHAVIORAL 1. PLEASURABLE, FRIENDLY ATMOSPHERE 4, WHEN USED: LIGHTING BUDGET PROJECT

DINING HALL OBJECTIVES 2. ENJOYMENT OF FOOD 5. Day ~% TYPE: c

3. GOOD RESOURCE UTILIZATION 6. Night~

BIOLOGICAL AND ACTIVITY NEEDS INFORMATION NEEDS HARDWARE SYSTEM FOOTNOTES

d >- k U NUMERICAL a BIOLOGICAL NEEDS l- e VISUAL SUB-ACTIVITIES INFORMATION NEEDS 0 CHARACTERISTICS OF VISUAL ENVIRONMENT CRITERIA

cc Routes, signs, layouts of objects and Positive, clear articulation of paths, nodes and areas by building a Unit of 0>

- building elements elements and graphics • :l

cc Measure 0'_

0> '"

Movement % 0... Adequate illumination, shadows, gradients: minimum disability cc>

Circulation information Levels, edges, obstacles, people, and other Relaxation - Stimulation 10 Physical Dangers moving objects glare, irrelevant disturbing pattern

20 Orientation in space Shape of space; relation to exterior Spatial and structural articulation

enclosure Nature of enclosing structure Clear windows, skylights

time Daylight reference No glaring light fixtures; relevant order of focus for activity weather View of sky, winds, rain, sunlight, artwork, and characteristics of space

Restful visual activity of interest and other people No mixed color sources on similar surfaces in similar

non-activity Isolation when desired circumstances

No distraction by high signal-noise ratio No disturbing color Illuminated wall and ceiling surfaces during the day to balance

upsetting constancies Expected relationship of brightness: window brightness and to relate to exterior daytime

upsetting expectations interior surfaces to exterior conditions

b ACTIVITY NEEDS C PARTI- f VISUAL 9 EVENTS h i LOCATION j REMARKS I OBJECT m INFORM. NEEDS n NEG. P PRIME LIGHT SOURCE CHARACTERISTICS t REMARKS

AND CIPANTS OBJECTIVES HOR. VERT. CHAR. FACTORS q POSITION RELATIVE Color r 5 WAVE CHAR.

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EATING/DRINKING 20 FOOD 10 29 + -

DISHES, UTENSILS 5 1,11,1 -

TABLE & ROOM DECOR 5 29 14 + -

CONVERSATION 15 FACES, GESTURES, CLOTHING 15 2,9 + -

READING/BROWSING 5 MAGAZINES. BOOKS NOTICES 5 2,5 + + - RES

SOCIAL DANCING 5 SURROUNDINGS 5 DARKEN SPACE 14 + DIMMING: FLEXIBLE

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LECTURE 5 FACES, GESTURES,

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VIEWING PERFORMANCE 5 PEOPLE 4 12 + -PROPS 1

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SERVING 5 UTENSILS, FOOD 4 1,2,9 11,13 + -

FLOOR 1 Ll

CLEANING 5

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