color perceptions of deuteranopic and protanopic observers

U. S. Department of CommerceNational Bureau of Standards

Research Paper RP1922Volume 41# October 1948

Part of the Journal of Research of the National Bureau of Standards

Color Perceptions of Deuteranopic and ProtanopicObservers

By Deane B. Judd

It is well established that about 2 percent of otherwise normal human males are con-fusers of red and green from birth. There is considerable interest in the question: What dored-green confusers see? From a knowledge of the normal color perceptions correspondingto deuteranopic and protanopic red and green, we may not only understand better whycolor-blindness tests sometimes fail, and so be in a position to develop improved tests, butalso the color-deficient observer may understand better the nature of his color-confusionsand be aided to avoid their consequences. If an observer has trichromatic vision over aportion of his total retinal area, and dichromatic vision over another portion, he may givevalid testimony regarding the color perceptions characteristic of the particular form ofdichromatic vision possessed by him. Preeminent among such observers are those born withone normal eye and one dichromatic eye. A review of the rather considerable literature onthis subject shows that the color perceptions of both protanopic and deuteranopic observersare confined to two hues, yellow and blue, closely like those perceived under usual conditionsin the spectrum at 575 and 470 m/x, respectively, by normal observers. By combining thisresult with standard response functions recently derived (Bureau Research Paper RP1618)for protanopic and deuteranopic vision, it has been possible to give quantitative estimates ofthe color perceptions typical of these observers for the whole range of colors in the MunsellBook of Color. These estimates take the form of protanopic and deuteranopic Munsellnotations, and by using them it is possible not only to arrange the Munsell papers in waysthat presumably appear orderly to red-green confusing dichromats, but also to get imme-diately from the notations an accurate idea of the colors usually perceived in these arrange-ments by deuteranopes and protanopes, much as the ordinary Munsell notations serve todescribe the visual color perceptions of a normal observer.

I. IntroductionThe question, "What colors do color-blind

observers confuse?" is a very practical one, cap-able of objective solution by putting each color-blind observer to trial and noting his mistakes.For the two most common forms of partiallycolor-blind observers, deuteranopia and protan-nopia, each form comprising about 1 percentof the otherwise normal male population, a gen-eral answer, approximately valid for all observersproperly so classed, has been found and described[51, 81].1

The question, "What colors do color-blindobservers see?" is a more subtle one, involving afine point in the theory of knowledge, yet of con-siderable practical importance, too. Strictly

1 Figures in brackets indicate the literature references at the end of thispaper.

speaking, the subjective life of each observercannot be known to anyone else, and there is noway of knowing whether the perception of red byone normal observer bears any resemblance tothat which another normal observer calls by thesame name. In this sense it is also impossible todiscover what colors are seen by the partiallycolor-blind. However, from the similarity inresponses between normal observers, it is a fairlysafe conclusion that their color perceptions areclosely similar. In the same inductive sense,it is possible to discover how the color perceptionsof the color-blind are related to those of the normalobserver. It is one purpose of the presentpaper to review the evidence by which these areknown. A second purpose is to give a compre-hensive inter translation between normal colorperceptions of surface colors on the one hand and

Color-Blindness 247

protanopic and deuteranopic surface-color per-ceptions on the other.

The outstanding characteristic of protanopic anddeuteranopic observers is that they confuse bothred and green with gray, and indeed they confusered with green. For this reason they are rightlycalled red-green confusers, less aptly red-greenblind. Since to the normal eye red is nearly asdistinct from green as black is from white, it maybe deduced that red-green confusers fail to experi-ence both the normal red and the normal greenperception; but the deduction may not be pushedfurther. From a stimulus normally yielding red,a red-green confuser might perceive red or greenor some other of the normal color perceptions,or some perception not normally experienced.

The impossibility of passing from knowledge ofwhat colors are confused to knowledge of thosethat are seen by color-blind observers was recog-nized almost as soon as color-blindness was dis-covered. Thus we find Wilson [97] remarking in1855, " I t must be remembered, however, thatthere is no common language between the colour-blind and the colour-seeing/7 Then in 1880-81Holmgren gave essentially the argument of thepreceding two paragraphs in complete and cleardetail and published it in four languages [39, 40,42, 46]. Donders [15] in 1881 stated (p. 84), "Ifthey (the color-blind) name their colors yellowand blue, this by no means proves that they seeyellow and blue as we see them, but merely thatin our yellow and blue their colors appear mostcharacteristically." A year later v. Kries insertedthe argument into his early analysis of visual sen-sations [60], "For bilateral color-blindness thefacts are essentially different. Here is lacking thepossibility of comparing directly normal and ab-normal sensations with each other. The old state-ment that we cannot know what the color-blindreally sense, self-explanatory as it is, appears,however, still not always to have been fully andcompletely understood."

These repeated and clear explanations did not,however, prevent Edridge-Green [19] in 1911 fromgiving a "proof" that red-green confusers see redand violet by means of precisely the same argu-ments previously used by Pole [82] to "prove"from observations with his own color-blind eyesthat they see blue and yellow. These argumentsare invalid in either case, as pointed out explicitlyby Hartridge [27], but Pole's conjecture, for that

is all it was, was corroborated by later validevidence. After having convinced himself (oninsufficient ground) that his sensations were thesame as what normal observers call yellow andblue, Pole put forward in 1856 an original, verypractical suggestion (Roy. Soc, p. 176; Phil. Mag.,p. 285) now in widespread daily use, namely, " I thas been thought that the use of these colors (redand green) for railway and ship signals becomesdangerous where color-blind persons have toobserve them. This danger may be obviated byvery simple means—if the green be made a bluegreen at the same time that the red is a yellow red,they become quite as distinct to the color-blind asto the normal eyed." Present color specificationsfor marine and railway signaling pair a red slightlyon the yellow side with a nonyellowish green, andthis choice is also prevalent for stop and go signalsfor highway traffic. This plan has also been ex-tended only recently by the American StandardsAssociation [52] to the marking of industrialhazards.

The practical importance of inquiring into thecolor perceptions, in addition to the color confu-sions, of partially color-blind observers lies in thefact that resolution of this question facilitatesconsideration of precautions against the dangersof color-blindness and also aids in the design oftests for its detection. Thus Pole made his usefulsuggestion only after he had made a fortunateconjecture as to the connection between his colorvision and those of the normal eyed. By thisassumption he supplied himself with a terminologythat immediately suggested the kind of red andgreen safe for railway and ship signals. It is thethird purpose of this paper to develop a methodof expressing the color-perceptions of the averagered-green confuser in terms that are immediatelycomprehensible both to those trained in the inter-pretation of colorimetric coordinate systems andto the untrained alike. It is expected that thismethod will assist both normal observers and red-green-confusing observers to understand the rela-tion between their two systems and so aid inavoiding the undesirable consequences of red-green confusion.

II. Review of the Literature

It has been pointed out by Holmgren [42], by v.Kries [62], and doubtless by many others, that

248 Journal of Research

persons born with one normal eye and one color-blind eye give us our most direct evidence of thecolor perceptions of the color-blind. Less reliableevidence may be obtained from persons who con-fuse red and green because of diseases of the eyesor optic nerves, and who are therefore familiarwith normal colors through past experience beforebecoming afflicted. And, finally, some informa-tion may be obtained from the peripheral parts ofthe normal retina that respond with confusionssimilar to those of deuteranopia. Any observer,a portion of whose retinas yields normal colorvision while another portion yields either thekind of red-green confusion characteristic ofprotanopia or that characteristic of deuteranopia,can give valid testimony.

It is now a fairly well accepted view that red-green confusers see neutral colors (black, gray,white, silver, "colorless" and so on) normally, andchromatic colors of two hues, approximatelywhat normal observers call pure yellow and pure-blue [14], with little or no admixture of red andgreen. Evidence obtained from all three types ofadmissible observers consistently supports thisview. We shall, however, review the literature tosee whether this rough indication can be mademore precise.

1. Peripheral Parts of the Normal Retina

It has been widely stated in textbooks for manyyears that there is, in the normal eye, a retinalzone of considerable extent (perhaps 20° to 50°from the fovea centralis) within which yellow,blue, black, and white are perceived much as atthe fovea, but red-green distinctions are scarcely,if at all, possible. Since the luminosity functionof this region in a light-adapted state is substan-tially the same as normal [30, 61, 68 (p. 46)], theproperties of this retinal zone near the peripheryapproach those of deuteranopia, the distinctionsfrom deuteranopia being reduced visual acuity,reduced ability to distinguish both black fromwhite, and yellow from blue, and presence of aslight, instead of vanishing, ability to distinguishred from green. As a preliminary observationwill immediately show, the precise hues of theyellowish and bluish colors seen by means of thisretinal zone are hard to determine. A spectrumstimulus yielding a color of orange hue by fovealvision yields a progression of less and less reddishhues as it is moved more toward the periphery.

There are determinable for each observer, how-ever, within certain limits the wavelengths of thespectrum stimuli yielding colors of invariable hueregardless of retinal region stimulated. It isobvious that the hues of the bluish and yellowishcolors perceived by the nearly deuteranopic pe-ripheral region are to be found among these in-variable hues. Table 1 is extracted from asummary by Tschermak [95] and shows results offour investigators. As might be expected fromthe difficult nature of the observations and themany factors influencing the results [17; 69,p. 273], there is considerable difference betweenthe reports of the various investigators. Gold-mann's results refer to a protanomalous observer[24] and on this account have less weight than theothers. Some observers can make such obser-vations with good reliability (Hess, 2 to 3 m/xuncertainty), others less certainly (Dreher, 10m/x uncertainty); and there is furthermore a largeindividual difference (40-mjii spread amongDreher's three observers). Although Hess' re-sults refer to one observer only (himself), theyare probably as good as any, and have, at least,been the most widely quoted [30]. These resultsindicate the deuteranopic yellow to be a hue cor-responding, for normal vision under visual con-ditions, to about 575 m/x; and deuteranopic blueto be that corresponding to about 470 m^, withuncertainties of about 10

TABLE 1. Stimuli that yield bluish or yellowish colors ofinvariable hue, regardless of retinal region affected

Author

Hess [33]Baird [4]Dreher [17]..-.Goldmann [25]

Year

1889

1905

1912

1925

Wavelength of spec-trum stimulus yield-ing invariable hue,regardless of retinalregion

Yellowish Bluish

574.5

570

568

567

471

460

461

466

2. Red-Green Confusion Acquired ThroughDisease

Toxic agents and disease affecting the conduct-ing (transmissive) elements of the optical appa-ratus (nerve elements and connections, opticnerve, and 'tract) cause a progressive lessening ofthe ability to distinguish red from green. This

Color-Blindness 249

defect becomes progressively worse until red-greenblindness is reached, which is distinguished frominherited deuteranopia chiefly by its poorer light-dark discrimination. There is also some lesseningof the ability to distinguish yellow from blue,which may progress until total color-blindnessresults [59, p. 141; 68, p. 45]. The luminosity func-tion is essentially the same as for normal vision[57], and white, gray, and black are perceived in arelatively normal way. Kollner [59, p. 148] says,"In the dichromatic state the patient sees in thespectrum only yellow and blue, and the yellowcorresponds to the hue which is elicited in thenormal eye by light of wavelength 575 m/x, theblue to the hue corresponding to that of wave-length 471 mju." These facts, like those of periph-eral vision by the normal eye, indicate that thedeuteranopic observer sees a yellow like that cor-responding to about 575 mju for the normal ob-server, and a blue corresponding to about 470 m/x.

3. Unilateral Red-Green Blindness

Unilateral inherited defects of vision are prob-ably much more common than would be supposedfrom accounts of such cases appearing in theliterature. An Army physician observed in1920 [5], " I t has been recently discovered thatbecause a man has excellent color vision in oneeye he does not necessarily have it in the other/'And a recent estimate [66] places the incidence ofunilateral defects at about 4 percent of the totalcolor defectives. Since, however, color vision ofboth eyes is most frequently tested at the sametime, it follows that most unilateral defects gounnoticed [58, 66, 88]. Table 2 lists chronologicallyall cases of unilateral defects in color vision thatcould be uncovered by a reasonable search of theliterature. There are 40 original articles listedinvolving 37 cases, a case of unilateral protanopiabeing dealt with twice by Hippel [36, 37] and onceby Holmgren [42], a case of unilateral tritanopiabeing dealt with both by Kirschmann [54] and byDieter [13], a case of unilateral deuteranomalyboth by v. Kries [62] and by Trendelenburg [94]and one article by Bonner [101] mentioning twocases previously unreported.

It should be noted that the skill and resourcesof the several investigators varied over a widerange, so that both the type of defect for the

TABLE

Author

v. B a u m g a r t -ner [6].

Brischelll]Niemetscheck [77]-

Woinow[98]

Becker [7]Hippel [36]Holmgren [42]Hippel [37]Holmgren [44]Steffan[90]

Snell[88]

Hermann [32]Kolbe [56]Shufeldt [86].Donders [16]

E d r i d g e -Green [18],

Hering[31]_

Hess [34]Snell[89]

Kirschmann [54]Hilbert [35] ._ _Beevor [8]Piper [80]

Samojloff [85]

Kollner [57] -_.

Hayes [281Hegner [29] _Lohmann [65]

v. Kries [62]Goldschmidt [26].Bonner [10]

Jennings [48]

Bonner [11]

Dieter [13]M i l e s , B e a u -

mont [66].Miles, Craig [67]Neipperg [75]T r e n d e l e n -

berg [94].Sloan [87]

2. Unilateral defects of

Date

1858

18621868

1871

187918801881188118811881

1881

1882188218831884

1889

1890

18901892

1893189418941905

1906

1909

191119151917

191919191923

1925

J 1926j 1926

19271931

193119321941

1947

Probable cause of defect

Blow en eye

Attack of vertigoSkull-bone degenera-

tion.Noticed after head-

wound, but perhapsinherited.

Inheriteddo

____dododo

Apoplexy..

Skull fracture

UnknownInherited._ do. .

do

Probably retinitis

Optic-nerve atrophy. _

Nerve injury..Noticed after blow on

head, but perhapsinherited.

Inherited. do

Nerve injury _ _ ._ .do

Inherited

Optic-nerve atrophy. _

Inherited_.. .do

do

doGunshot head wound _.Optic atrophy (tuber-

culous).Noticed after blow on

head, but perhapsinherited.

Unknowndo

InheritedUnknown

Inheriteddo . .

do

color vision

Type of defect

Temporary achroma-topsia.

Temporary cyanopsia.Tritanopia and chlo-

ropsia.Atypical, red phobia.

Acromatopsia.Protanopia.

Do.Do.

Tritanopia.Approach to achroma-

topsia.Protanopia, deutera-

nomaly.Tritanopia.Red-green weakness.Red-brown confusion.Abnormal Rayleigh

equation.Tritanopia, yellow-

blue weakness.Approach to deuter-

anopia.Do.

Deuteranopia.

Tritanopia.Slight abnormalities.Achromatopsia.Achromatopsia, tritan-

opia.Abnormal Rayleigh

equation.Achromatopsia, tritan-

opia.Protanomaly.

Do.Abnormal contrast ef-

fects.Deuteranomaly.Protanomaly.Green weakness.

Red-green blindness.

Achromatopsia.Red-green blindness.Tritanopia.Red-green blindness.

Do.Do.

Deuteranomaly.

Deuteranopia.

defective eye and the degree of approach to thenorm in cases having one supposedly normal eyeare subject to various degrees of doubt. Simi-larly, in many cases the report of the probablecause 6f the defect is based on very incompletedata. If there were no evidence of disease or


injury, the defect is listed as probably inherited.In one case, however, it is known definitely thatthe defect was inherited; the subject found by v.Kries to have unilateral deuteranomaly was foundlater [94] to have transmitted a bilateral deutero-form defect to his daughter. Table 2 is intendedto give brief summaries of all cases of unilateral

. defects of color vision, and the information is asprecise as can be given in a few words; but thesesummaries are, of course, often unsatisfactorysubstitutes for the original articles that should beconsulted if more detailed information is desired.

Since many of these cases are to be neglected ashaving no bearing on the color perceptions of pro-tanopic and deuteranopic observers, it is conven-ient to introduce here the definitions of the termsby which the type of defect has been indicated intable 2.Trichromatism—a. type of vision in which the

colors seen require in general three independ-ently adjustable primaries (such as red,green, and blue) for their duplication bymixture. Normal vision is one form oftrichromatism.

Dichromatism—a type of vision in which the colorsseen require in general two independentlyadjustable primaries (such as red and green,or purple and yellow) for their duplication bymixture.

Monochromatism—a type of vision in which thecolors seen require only a single adjustableprimary to match them. Any light mayserve as the primary. ,

Protanomaly—a type of trichromatism in whichthe relative luminosity function is too low atthe longwave end to fall within normal limits,and in which an abnormally large proportionof red in a red-green mixture is required tomatch a given yellow.

Deuteranomaly—a type of trichromatism in whichthe relative luminosity function falls within

'normal limits and in which an abnormallylarge proportion of green is required in a red-green mixture to match a given yellow.

Protanopia—a type of dichromatism in which redand blue-green are confused, but no abnormalproportion of red plus green is required tomatch a given yellow, and the relative lumi-nosity function is too low at the longwaveend to fall within normal limits.

Deuteranopia—a type of dichromatism in which

purplish red and green are confused, but noabnormal proportion of red and green isrequired to match*a given yellow, and therelative luminosity function falls within nor-mal limits.

Tritanopia—a type of dichromatism in whichreddish blue and greenish yellow are confused.

Achromatopsia—a type of monochromatism inwhich all colors are perceived as neutral (suchas black, gray, and white).

Chloropsia—green vision.Cyanopsia—blue vision.Rayleigh [88] equation—the proportions of red and

green required in a mixture to match a givenyellow. Usually spectrum red (670 m/x) ismixed with spectrum green (535 m/*) in suchproportions as to match spectrum yellow (589

It would seem that only cases of protanopia anddeuteranopia listed in table 2 need be considered,but it has often been noted [28, 62 (p. 148), 74]that under unfavorable conditions (such as smallangular extent of observing field, reduced observ-ing time [29], low field luminance, or dark sur-rounding field) protanomalous and deuteranomal-ous observers make the same mistakes as pro~tanopes and deuteranopes, and respond as if theyhad dichromatic rather than trichromatic visualsystems (red-green confusion, presence of a neutralpoint in the spectrum near 495 m/*, and so on).On this account, many color-perception tests failto differentiate red-green confusers into groups ofdichromats and trichromats. It is possible there-fore to obtain information concerning the colorperceptions characteristic of dichromatic visualsystems from unilateral protanomaly and uni-lateral deuteranomaly, provided attention is paidto observations obtained by such observers underconditions that reduce these systems to, or nearlyto, dichromatism. Table 3 lists all unilateralcases from which information regarding protanopicand deuteranopic color perceptions can be gleaned.It also includes a bilateral case reported by Nagel[72], which has a bearing on deuteranopic colorperception. In this case the fovea was dichro-matic, the periphery trichromatic, quite beyondthe vestigial trace often reported by dichromats.Cases of unilateral achromatopsia and tritanopialisted in table 2 have been omitted, togetherwith those of red-green confusion not givinginformation regarding color perceptions (Snell,

Color-Blindness 251

Kolbe, Shufeldt, Hegner, Lohmann, Jennings,Neippert, Bonner, and Miles and Beaumont).Cases of slight abnormality not approachingdichromatism are also omitted (Donders, Hilbert,Samojloff).

The case of atypical unilateral sense disturbancereported by Woinow [98] has been omitted, becausethe report is contradictory. The subject wasreported to be deuteranopic (green blind) in oneeye, and measurements by rotating sector disksindicated confusion of both red and green withgray. There was, however, hysterical fear of redparticularly from the eye which, as we have seen,under some conditions could not distinguish redfrom gray Furthermore, all objects seen by thiseye were tinged with red, but spectrum yellowappeared blue. There is no evidence, except thislatter rather confusing report, that the colorsystem of the defective eye was dichromatic; itmight have been monochromatic. Reports of thesubject in other sense fields (taste, temperature,smell, hearing) indicated a profound psychicdisturbance.

The case of temporary cyanopsia reported byBrische has also been omitted; the visual systemseems to have been monochromatism, black, gray,and white objects, and all parts of the spectrum,appearing blue.

In table 3 the indicated perceptions are specifiedin many cases simply by color name, and we see,as before, that unilateral defects of vision indicatethat the protanopic and deuteranopic perceptionof white is normal, and those of hue are some kindof a yellow and some kind of a blue. In othercases these indications have been made more exactby direct comparison of the spectrum colors viewedby the defective eye with those of the same spect-rum viewed by the normal eye. Orange, for ex-ample, is seen as yellow by the dichromatic eye,as is also yellow green; but the part of the spectrumwhose hue is the same for both the normal and thedefective eye serves as a specification for the par-ticular kind of yellow sensed by the dichromaticeye; that is, we can say from such evidence thatthe dichromatic yellow is like that perceived atsome certain portion of the spectrum by the normaleye. Five of the entries in table 3 are of thisnature. Four out of five of these entries refer tosubjects who had in the defective eye slight, ratherthan vanishing, ability to distinguish red fromgreen, but reports of hue difference between the

two eyes could still be made and the spectral region-yielding the same hue for both eyes determined.In general, it will be noted that for both the deuter-anopic and protanopic forms the yellow is closelylike that of the spectrum at 575 m/z to the normaleye, and the blue like that of 470 m/x. This agreeswith indications for the deuteranopic form ob-tained from the periphery of the normal retina andfrom acquired bilateral color-blindness.

The three exceptions to this generalization are,first, the wavelength 589 m.ju found by Hippel forhis unilaterally color-blind observer; second, thedesignation, orange-yellow, shown for Gold-schmidt's case of unilateral protanomaly; andthird, the contradictory report by Sloan's uni-lateral deuteranope. The first two exceptionssuggest that some protanopes, at least, see orange-yellow instead of the slightly greenish yellow of575 m/x. Hippel, however, depended on the ob-servation of flame spectra under the unfavorablecondition of a dark background and did not reporttests of any yellowish spectrum color other than589 m/x (that is, none nearer than this to 575 mju),so his finding may merely be an imprecise check of575 m/x. Furthermore, the report of orange-yellow is rendered doubtful by the report byHolmgren of greenish yellow (" greenish yellow,or citron yellow, not golden yellow") for the samecase [42] examined by means of dyed wools. Inthe second exception, it was stated [26] rather in-explicitly that for the defective eye, "the greenappeared in the spectrum stretched out into theyellow, and the blue stretched out into the violet,. . ." Neither of these reports can be taken asestablished exceptions to the otherwise consistentindication that the yellow and blue of red-greenconfusers are, respectively, closely what the nor-mal eye sees in the spectral regions near 575 and470 m/x.2

Some writers [28] have classified the Hering andHess cases as probably protanomaly because of

2 Since the indicated perceptions for both protanopic and deuteranopicvision are not significantly different, no extended discussion of discrepanciesin classification of the unilateral defects shown in table 3 is required. Forthe same reason, it is unimportant for the present purpose to determinewhether the defect is inherited or acquired. However, it may be remarkedthat the classification by Hippel of his patient as what we now call deu-teranopic rests on his failure to find the spectrum shortened on the long-waveend relative to that for the normal eye, all of the various spectral emission linesused being either visible to both eyes or invisible to both. The classificationof protanopia, however, is firmly grounded not only on Holmgren's findingbased upon the Holmgren wool test, which includes a chromaticity method ofdiagnosing protanopia, but also on Hippel's own report that the brightestpart of the spectrum for the defective eye was shifted considerably toward theshort-wave end relative to that for the normal eye.


the statement that the long-wave end of thespectrum was shortened. This minor shorteningis to be expected because of the partial impair-ment of the yellow-blue and light-dark senses, aswell as the almost complete disappearance of thered-green sense. It is not to be confused [68,(p. 45)] with the much larger departure fromnormal characteristic of protanopia, designated byHering as "blue-sighted red-green blindness."

The reclassification of Hayes' subject from pro-tanopia to protanomaly is based upon the fact thatthe normal setting of a red plus a green by diskmixture to match a yellow plus black plus whitewas found by the subject's defective eye to bemuch too green. To satisfy the defective eye, shehad to put by far more red in the first mixture.Hayes' conclusions are sound if translated intoaccepted terminology.

A further word is required regarding the ap-parently contradictory report by Sloan's unilateraldeuteranope [87] that, on the one hand, the huesseen are like Munsell 5Y 5/5 (dominant wave-length 575 mju) and 3PB 5/5 (dominant wavelength478 m/x), and that, on the other they are like thespectrum at 584 and 452 m/x. There are severalpossibilities to be explored, but it will be sufficientfor the present to point out that if both eyes ofthis subject had an abnormally large amount ofocular pigmentation and so were provided with apermanent adaptation to reddish yellow, the dis-crepancy would be explained. The same explana-tion would also account for the discrepancy be-tween the wavelength of neutral point estimatedfrom the Munsell 5/5 locus (498 m/x, which istypical of deuteranopia [50, 51]) and that estimateddirectly from the spectrum (503 my, correspond-ing to reddish yellow adaptation). A more com-plete study of this observer might be worth while.

III. Agreement with Theories of ColorVision

The evidence just reviewed that red-green con-fusers see yellow and blue does not, of course,prove that all red-green confusers have thosecolor perceptions, though the absence of reliableconflicting evidence renders such a conclusionhighly probable. Thus, Parsons [79, p. 191] re-marked in 1924, "Most observers think that thetwo sensations experienced (by protanopes anddeuteranopes) correspond most closely to normalyellow and blue. Uncomplicated cases of uni-

lateral congenital colour blindness would affordvaluable evidence . . .". Similarly, in 1927,Dieter [13, p. 79] said, "Only if still more cases ofthe same kind are completely analysed will therebe sufficient ground for the alluring possibility oftheoretical appraisal." Unilateral color-blindness,however, has already had an important influenceon color theory.

During the period (1880-1920) when theexperimental facts of protanopic and deuteranopiccolor perceptions were being established, the con-troversy between the three-components (Young-Helmholtz) theory of color vision and opponent-colors (Hering) theory reached its height [64].

According to the three-components theory,there are in the normal retina three independentphotosensitive mechanisms, one sensitive pre-ponderantly to the long-wave portion of thespectrum and yielding a red response, anothersensitive preponderantly to the middle portion ofthe spectrum and yielding a green response, andthe third sensitive preponderantly to the short-wave portion of the spectrum and yielding a blueor violet response.

According to the opponent-colors theory, thereare in the normal visual mechanism three pairs ofopposing processes, a black-white pair, whichcancels to leave gray, and two chromatic pairs,blue-yellow, and red-green, which cancel to graywhen both members of the pair are excited equally.

Red-green blindness according to the three-components theory comes from failure of eitherthe red-component (protanopia) or the green-component (deuteranopia), leading to the indica-tion that protanopes must see only mixtures ofgreen and violet, and deuteranopes, only mixturesof red and violet. But, by the opponent-colorstheory, only one type of red-green blindness is tobe expected, that arising from elimination of thered-green process, leaving the perceptions whiteand black, blue and yellow.

The case of unilateral protanopia (Hippel,Holmgren, table 3) was a blow to the original formof three-components theory. It showed that onered-green blind eye, at least, saw yellow and blue,not green and violet. The three-componentstheory can be thrown into a form accounting bothconveniently and precisely for the red-green con-fusions of protanopes and deuteranopes [51], butthis single base of unilateral color-blindnessshowed that it is not a reliable guide to what they

Color-Blindness803370—48 2

253

TABLE 3. Cases of unilateral defect of vision -giving information regarding protanopic and deuteranopic color perceptions

Author

Hippel[36] ...Holmgren [42]Hippel[37[Hering[31]Hess [34]Nagel[72]Hayes [28]v. Kries[62]Goldschmidt [26]Sloan [87]

Date

1880.1881..1881.

1890-

1890.1905-

1911.

1919.

1919.1947.

Classification of the defect

Author's own

DeuteranopiaProtanopiaDeuteranopiaApproach to deuteranopia....l-.doDeuteranopiaProtanopiaDeuteranomalyProtanomalyDeuteranopia

Present

Protanopia-. . . . .do

-do-Approach to deuteranopia-

doDeuteranopiaProtanomalyDeuteranomalyProtanomalyDeuteranopia

Indicated perceptions

YellowGreenish yellow..Like 589/zYellowLike 575 M

Yellowdo

Like 573^Orange, yellowLike 5 Y 5/5, also 584 m/«_

Blue.Violet blue.Blue.

•* Do.Like 471 mM.Blue.

Do.Like 464 to 480 m/x.Blue.Like 3PB, 5/5, also 452

see. The opponent-colors theory, on the otherhand, received dramatic support from the colorperceptions reported for this case. This lattertheory, however, does not account for two forms ofred-green blindness, but only one, deuteranopia.

It may be said, therefore, that both of thesesimple visual theories received fatal blows fromdiscovery of the facts of protanopia and deuter-anopia. Some advocates of the three-componentstheory refused to be impressed by the Hippel-Holmgren case of unilateral protanopia. Holm-gren, himself, continued to use the terms, "redblind", ."green blind" and "violet blind", andoffered a prize of 400 crowns to anyone who wouldbring to his attention a case of unilateral "greenblindness" [45]. Some three-component advocatestook refuge in Fick's [21, 22] suggestion that red-green blindness results, not from the completefailure of one of the three components, the red orthe green, but from the receptors for red and greenhaving identical photo-sensitive substances, eitherthat normally used for red or that normally usedfor green. Other advocates of the three-compon-ents theory (Konig, v. Kries) eventually took upthe very similar theoretical position [54a, 60(p. 169)] originally proposed by Bonders [15] thatthe three-components theory holds for processesin one stage or zone of the visual mechanism(perhaps the photosensitive substances), whereasthe opponent-colors theory holds for processes ina later stage or zone (perhaps the optic nerve).This view is known as the zone or stage theory ofvision. Furthermore, a very able advocate of theopponent-colors theory, G. E. Miiller, adopted atheoretical view which, although divergent indetail and more elaborated, was essentially in

agreement with the zone theories favored byDonders, Konig, and v. Kries. All of these theoriesallow for protanopic and deuteranopic perceptionof yellow and blue, though that of Miiller doesnot require it for protanopes. Mtiller remarks(p. 49), "If the color-blind is a deuteranope, hischromatic color sensations must therefore (by thistheory) be pure yellow and pure blue . . . .It is otherwise with protanopes. If in an indi-vidual outer red-green sensitivity is absent, itmakes no difference in his behavior, either inpractical living or in any investigation, whetherthe remaining greenish-yellow and reddish-blueprocesses excite only yellow and blue in the opticnerve, or whether, . . ., they excite greenish-yellow or reddish-blue sensations, or whether, . . .they excite only green and red, or . . .even only green and blue, or . . . yellow and red.An individual lacking outer red-green sensitivitywill give exactly the same color equations, exactlythe same spectral positions of brightness maximumand neutral point regardless of whether hisgreenish yellow and reddish blue processes evokenerve excitations corresponding to the like-namedexcitations (yellow and blue) or unlike-namedexcitations (green and red), or by simultaneousaction of both sorts, excitations of exactly thesame kind as the processes themselves. We wouldtherefore not be particularly astonished if it wereestablished definitely in a unilateral case of pro-tanopia that the yellow sensation experiencedactually was somewhat greenish and that the bluesensation experienced actually was somewhatreddish, and we would not believe that the groundwas disappearing under our feet if sometime thereshould occur a (quite improbable) case establishing


the two chromatic color sensations of a protanopiceye as the pure-green sensation and the pure-redsensation."

Since all theories of vision with any pretenseof being complete provide for the perception ofyellow and blue by red-green confusers, and sincea reasonable search of the literature has failed touncover any reliable evidence against this indica-tion, it is proposed to build a method of designatingprotanopic and deuteranopic perceptions of sur-face colors on the finding that such observers seea yellow and a blue like those seen by the normalobserver in the spectrum near 575 and 470 m/x,respectively. The consequences of this choice ofhues are bound to appear correct to binocularred-green confusers. These consequences can becontradicted only by observers having unilateraldefects; and the probability of such contradictionarising may be estimated from the fact that theeight cases recorded so far (see table 3) fail tocontradict it.

IV. Derivation of Deuteranopic andProtanopic Munsell Notations

Object-color perceptions by normal observersare most commonly described in terms of theattributes, hue, lightness, and saturation [78] de-fined [2] as follows:

11 Hue is the attribute which determines whetherthe color perception is red, yellow, green, blue,purple, or the like.

"Lightness is the attribute which permits anobject-color perception to be classified as equiv-alent to some member of the series of graysranging between black and white.

"Saturation is the attribute of an object-colorperception which determines the degree of itsdifference from the gray of the same lightness/7

The Munsell color system is based upon thismethod of description. Munsell hue, value, andchroma, are intended to correspond to hue, light-ness, and saturation, respectively, and the samplesin the Munsell Book of Color [70] when viewed indaylight by a normal observer under usual viewingconditions (daylight adapted eye, light to medium-gray surrounding field) yield color perceptionssuch that Munsell hue correlates closely with theperceived hue, Munsell value with the perceivedlightness, and Munsell chroma with the perceivedsaturation. A method has been developed [49] bymeans of which readily understood color names

may be found for any color from its Munsellnotation.

When the samples of the Munsell Book of Colorare viewed by a protanopic or a deuteranopic ob-server, however, the color perceptions obtained arenot even approximately indicated by the Munsellnotation. It is proposed to develop a method ofderiving protanopic and deuteranopic Munsellnotations, analogous to the present normalMunsell notations, that will correlate with thecolor-perceptions that red-green-blind observersobtain from objects viewed in daylight uuderusual conditions. It has been shown [51] that thecolor confusions of red-green-blind observers canbe found from three numbers (Ky Wp, Wd) re-lated to the tristimulus values (X, Y, Z) of theICI standard observer by the transformationequations: *

Wv= -0.460 X+1.359 F+0.101 Z, (1)Wd=Y. \

Any two colors having identical values of K andWp are identical to the average protanope; thosehaving identical values of K and Wd are identicalto the average deuteranope. Figure 1 shows inarbitrary units the values of K, Wp, and Wd forall parts of a spectrum of unit irradiance per unitwavelength.

500 600WAVELENGTH IN m^t

700

FIGURE 1

One of each of the two pairs of numbers (Wd,Wp), used in judging equivalence of colors fordeuteranopic and protanopic observers, refers tothe luminous aspect of the color (luminance for aself-luminous area, luminous directional reflect-

Color-Blindness 255

ance for a surface), the other number, K, of eachpair taken relative to the first refers to the chro-matic aspect. For the ICI observer, luminousdirectional reflectance is customarily expressedrelative to that (Yo) of magnesium oxide. Byanalogy we take Wd/(Wd)0= Y/Yo for deuteranopicluminous directional reflectance, and

Wp _ -0.460X+1.359Y+0.101ZTOo~-O.46OXo+1.359 Y0+0.10lZ0'

for protanopic luminous directional reflectance.But since for magnesium oxide it is customary totake X0=0.9804, Yo= 1.0000, and Zo= 1.1512,protanopic luminous directional reflectance maybe written simply as 0.9733Wp.

It is customary to specify the chromatic aspectof a color for the ICI standard observer by meansof trichromatic coordinates, or chromaticity co-ordinates x, y, and z. By analogy with this prac-tice, the chromaticity coordinates for deuteranopicand protanopic observers are the dichromatic co-ordinates (wd, kdj wpy kp) defined as follows:

(2d)d d / ( d )

Y/(Y+Z)=y/(y+z)=yKl-x),kd=K/(Wd+K) =Z/(Y+Z) =

Wp ^-0.460X+1.359 F+0.101ZWp+K -0.460X+1.359F+1.101Z

0.561^+1.258^+0.1011.561aH-0.258y+1.10l'

K

~WP+K -0.460JM-1.359 F+1.101Z

_ l.OOO—x—y— 1.561z+0.258y+1.10l"

From eq 2d and 2p it will be noted that wp and kp

sum to unity; likewise, wd and kd. Hence onlyone of the dichromatic chromaticity coordinatesneed be used. We will use wd and wp, which maybe taken as measures of the deuteranopic andprotanopic "warm" quality, respectively. Accord-ing to the data and views already summarized insections II and III, it is legitimate to take themmore precisely as indications of "yellowness."

Since for the approximately 400 samples of theMunsell Book of Color, the tristimulus values,X, Yf Z, have already been evaluated fromspectrophotometric measurements [23, 53], it is

a simple matter to compute Wd/(Wd)o and wd

from eq 1 and 2d, and so arrive at a specificationof deuteranopic luminous directional reflectanceand chromaticity. The results are shown intable 4. Similarly there have been computed forthese 400 samples values of WP/(WP)O and wp,which serve as specifications of protanopic lumi-nous directional reflectance and chromaticity,respectively. These results are shown in table 5.In both tables 4 and 5, the samples have beenarranged in a sequence, which would appearorderly to the average deuteranope (table 4) orprotanope (table 5). The samples were firstarranged according to reflectance, and, as expected,for deuteranopic vision were found to form sevengroups of nearly constant reflectance (one foreach of the Munsell values 2 to 8) with definitereflectance gaps separating them. The samplesof each group are arranged according to yellow-ness, approximately as indicated by the chro-maticity coordinate, wd. Also, as expected, nosuch grouping was found after arranging thesamples according to protanopic reflectance.However, the samples were arranged arbitrarilyinto 14 groups (one for each of the Munsell values2.0, 2.5, . . . 8.5) so that the protanopic reflec-tance of each sample in one group is both lowerthan all of those in the group above and higherthan all of those in the group below. Withineach of these 14 groups the samples were arrangedaccording to yellowness, approximately as indi-cated by the chromaticity coordinate wp.

From the first three columns of tables 4 and 5,it may be seen that an arrangement that seemsorderly to a deuteranope or protanope may con-tain outstanding irregularities to a normal ob-server. For example, the first four entries in table4 are Y 8/12, Y 8/10, 10Y 8/8, Y 8/8. The secondcolumn indicates that these samples all havereflectances close to 0.58; that is, the colors ofthese surfaces appear to the average deuteranopeas well as to the average normal observer to beabout equally light. The third column indicatesthat the first sample is the yellowest and fourththe least yellow. With the exception of the thirdsample (10Y 8/8), this classification accords withthat of the normal observer, which is indicatedclosely by the Munsell notation (Hue Value/Chroma) Y 8/12, Y 8/10, Y 8/8. The thirdsample, however, is a more greenish yellow thanthe others and for the normal observer does not


fit into the series. In this instance table 4 hasserved to indicate with some precision the kind ofgreenish yellow that the average deuteranopemay be expected to confuse with a certain groupof yellows. It indicates in general exactly thered-green confusions characteristic of deuter-anopia. Table £ indicates in a similar way thered-green confusions characteristic of protanopia.

TABLE 4. Deuteranopic arrangement

TABLE 4. Deuteranopic arrangement—Continued

Munsellbook nota-

tion

5Y 8/125Y 8/10

10Y 8/ 85Y 8/ 85Y 8/ 8

5GY 8/ 810YR 8/ 8

6Y 8/610Y 8/ 6

5GY 8/ 610YR 8/ 6

5Y 8/410Y 8/ 4

10GY 8/ 65GY 8/ 4

10YR 8/ 4

10GY 8/ 45YR 8/ 410R 8/ 46Y 8/2

5GY 8/ 2

5G 8/65YR 8/ 2

5G 8/ 46G 8/ 25R 8/4

10G 8/ 2N 8/

5R 8/ 210RP 8/ 610RP 8/ 4

5BG 8/ 25RP 8/ 25RP 8/ 65RP 8/ 4

10BG 8/ 2

5B 8/ 25P 8/2

10P 8/ 45B 8/ 4

10B 8/ 2

5PB 8/ 210PB 8/ 2

P 8/ 4

Deuteran-opic re-

Wd = Y

0.5706. 5784.6035.5794.5732

.6022

.6049

.5784

.5996

.5929

.6114

.5651

.5997

.5793

.6041

.5972

.6181

.5970

.6115

. 5570

. 5851

.5595

.5917

.5881

.5694

.5862

. 5965

.5751

.6021

.6251

.6107

.6082

.6435

.6058

.6050

.6258

.6179

.6897

.6182

.6025

.6514

.6380

.6499

.5940

Deuteran-opic chro-maticity

coordinate,Wd

0.8911.8578.7918.7660.7606

.7464

.7064

.6681

.6664

.6605

.6263

.5851

.5827

.5720

.5719

.5579

.5406

.5311

.5156

.5141

.5107

.4964

.4949

.4899

.4847

.4834

.4806

.4700

.4699

.4693

.4678

.4656

.4633

.4611

.4588

.4557

.4361

.4330

.4289

.4272

.4170

.4139

.4099

.4004

Munsell renotations

Deuteranopic

5Y 7.9/12.25Y 7.9/11.05Y 8.1/ 9. 25Y 7.9/ 8. 25Y 7.9/ 8.1

6Y 8.1/ 7.95Y 8.1/ 6.95Y 7.9/ 5. 75Y 8.0/ 5. 75Y 8.0/ 5. 55Y 8.1/ 4. 7

5Y 7.8/ 3.45Y 8.0/ 3.45Y 7.9/ 3.15Y 8.1/ 3.25Y 8.0/ 2.8

5Y 8. 2/ 2.35Y 8.0/ 2.05Y 8.1/ 1.65Y 7.8/ 1. 55Y 8.0/ 1. 5

6Y 7. 8/ 1.15Y 8.0/ 1. 05Y 8.0/ 0.95Y 7.9/ 0. 85Y 8.0/ 0. 7

5Y 8.0/ 0.65Y 7.9/ 0.45Y 8.1/ 0.45Y 8. 2/ 0.45Y 8.1/0.3

5Y 8.1/ 0. 35Y 8.3/ 0. 25Y 8.1/ 0.15Y 8.1/ 0.1

5PB 8. 2/ 0.4

5PB 8. 2/ 1. 75PB 8.0/ 1.85PB 8. 2/ 2. 25PB 8.1/ 2.35PB 8.3/ 3.1

5PB 8.3/ 3.25PB 8.3/ 3.45PB 8.0/ 3.9

Normal

5.5Y 7.9/12. 35.5Y 7.9/11.1

0.5GY 8.1/ 9.15. 5Y 7.9/ 8. 25.5Y 7.9/ 8.3

4. 5GY 8.1/ 8. 70.5Y 8.1/ 7.64.5Y 7.9/5.8

0.5GY 8.0/ 5.75.5GY 8.0/ 6.29.0YR 8.1/ 5. 5

4.0Y 7.8/ 3.5l.OGY 8.0/3.49. 5GY 7.9/ 5.16.0GY 8.1/ 3.69.0YR 8.0/ 3.4

0.5G 8. 2/ 4.04.0YR 8.0/ 3. 510. OR 8.1/ 3. 73. 5Y 7. 8/ 1. 6

6.0GY 8.0/ 1.6

6. 5G 7.8/ 4. 74.0YR 8.0/ 2.0

5. 5G 8.0/ 3. 34. 5G 7. 9/ 2.13 5R 8.0/ 3.6

5.0G 8.0/ 2.02. 5GY 7.9/ 0. 3

2. OR 8.1/ 2. 28. 5RP 8. 2/ 3.69.5RP 8.1/ 2.7

1.0BG 8.1/ 2.08.0RP 8.3/ 1.96.5RP 8.1/ 3.45.5RP 8.1/ 2.85.0BG 8.2/ 1.9

4. OB 8. 2/ 2. 25. OP 8.0/ 2.57. 5P 8. 2/ 3. 54. OB 8.1/ 2.9

1.0PB 8.3/ 3.0

5.0PB 8.3/ 3.27.5PB 8.3/3.4

4.5P 8.0/ 4.8

Munsellbook nota-

tion

Y 7/10Y 7/8

10YR 7/1010Y 7/ 8GY 7/10

YR 7/1010YR 7/ 8

GY 7/ 810Y 7/ 6

Y 7/ 6

GY 7/ 6YR 7/ 8

10YR 7/ 610GY 7/ 8

YR 7/ 6YR 7/6

Y 7/ 410R 7/ 810Y 7/ 4

10GY 7/ 6GY 7/4

10YR 7/ 4YR 7/ 410R 7/ 6

10GY 7/ 410R 7/ 4

Y 7/ 2R 7/8

GY 7/ 2R 7/ 6

YR 7/ 2

G 7/6

R 7/4G 7/ 4

10RP 7/ 8G 7/ 2

10RP 7/ 65R 7/ 2

10G 7/ 410RP 7/ 4

RP 7/ 2

RP 7/4BG 7/ 2

N 7/RP 7/6BG 7/4

RP 7/ 8B 7/ 2

10P 7/ 410BG 7/ 4

10P 7/ 6

P 7/ 210P 7/ 8PB 7/ 2

B 7/ 410PB 7/ 4

Deuteran-opic re-

IlCCtclIlCc,

Wd = Y

0.4189.4220.4179.4440.4263

.4178

.4397

.4512

.4334

.4158

.4509

.4356

.4347

.4399

.4262

.4180

.4282

.4290

.4439

.4507

.4369

.4602

.4376

.4550

.4571

.4537

.4454

.4244

.4261

.4452

.4375

.4381

.4402

.4340

.4412

.4231

.4551

.4521

.4672

.4397

.4727

.4885

.4729

.4433

.4955

.4634

.4845

.4718

.4657

.4555

.4675

.4108

.4735

.4907

.4575

.4498


coordinate,Wd

0.8502.8430.8405.8358.8160

.7614

.7571

.7437

.7406

.7286

.6867

.6851

.6818

.6509

.6143

.6134

.6084

.6071

.6053

.6046

.5910

.5848

.5567

.5559

.5486

.5316

.5199

.5188

.5177

.5099

.5058

.5030

.4973

. 4948

.4801

.4777

.4773

.4766

.4734

.4732

.4601

.4590

.4589

.4562

.4533

. 4522

.4494

.4348

.4285

.4244

.4228

.4206

. 4125

.4125

.4092

.3982

Munsell renotations

Deuteranopic

5Y 6.9/ 9.75Y 6.9/ 9.65Y 6.9/ 9.45Y 7.1/ 9. 55Y 7.0/ 9.0

5Y 6.9/ 7.45Y 7.1/ 7. 45Y 7.1/ 7.15Y 7.0/ 7.05Y 6.9/ 6.4

• 5Y 7. ] / 5. 75Y 7.0/ 5.65Y 7.0/ 5. 55Y 7.1/4.85Y 7.0/ 3.95Y 6.9/ 3.8

5Y 7.0/ 3.75Y 7.0/ 3. 75Y 7.1/ 3.65Y 7.1/ 3.65Y 7.0/ 3.3

5Y 7.2/ 2. 55Y 7.0/ 2. 55Y 7.2/ 2. 55Y 7.2/ 2.35Y 7. 2/ 1.8

5Y 7.1/ 1.65Y 7.0/ 1. 75Y 7.0/ 1.75Y 7.1/ 1.35Y 7.0/ 1.2

5Y 7.0/ 1.15Y 7.1/ 1.05Y 7.0/ 0.95Y 7.1/ 0.65Y 7.0/ 0. 5

5Y 7.2/ 0.55Y 7. 2/ 0. 55Y 7.2/ 0.45Y 7.1/ 0.45Y 7.3/0.1

N 7.4/N 7.3/

5PB 7.1/ 0. 25PB 7. 4/ 0.35PB 7. 2/ 0.3

5PB 7.4/ 0.45PB 7.3/ 1. 55PB 7.2/ 1.95PB 712/ 2. 25PB 7.2/ 2.3

5PB 6.9/ 2.65PB 7.3/ 2.95PB 7J4/ 3.05PB 7:2/3.05PB 7.1/ 3.7

Normal

5.0Y 6.9/ 9.76.0Y 6.9/ 9.51. OY 6.9/10. 5

• 10. OY 7.1/ 9.34. OG Y 7.0/ 9. 5

5.5YR 6.9/10.10. 5Y 7.1/ 8.3

5. OG Y 7.1/ 8 00. 5GY 7.0/ 6.9

4. 5Y 6.9/ 6.0

5J0GY 7.1/ 6.44. 5YR 7.0/ 8. 210.0YR 7.0/ 6.310 0GY 7.1/ 8.33. 5YR 7.0/ 6.03.5YR 6.9/ 5.9

4. OY 7.0/ 3.810. OR 7.0/ 7. 5

1.0GY 7.1/ 3.610.0GY 7.1/ 6. 55.5GY 7.0/ 3.8

9.0YR 7.2/ 3.83.0YR 7.0/ 4.1

9. OR 7. 2/ 5. 710. OG Y 7. 2/ 4.1

8.5R 7.2/ 4.7

4.0Y 7.1/ 1.63. 5R 7.0/ 7.0

5.5GY 7.0/ 1.83. 5R 7.1/ 5. 7

3.0YR 7.0/ 2.1

7. OG 7.0/ 6.13. OR 7.1/ 5. 26. 5G 7.0/ 4.3

9.0RP 7.1/ 5.86. 5G 7.0/ 2.1

9. 5RP 7.2/ 4. 72. 5R 7.2/ 2.6

0.5BG 7.2/ 3.99. 5RP 7.1/ 3. 56. 5RP 7.3/ 2.3

6.0RP 7.4/ 3.33.5BG 7.3/ 2.17. 5PB 7.1/ 0.15.0RP 7.4/4.44.5BG 7.2/ 3.4

4.>5RP 7.4/ 4.93. 5B 7.3/ 2. 2

10. OP 7.2/ 4.00. 5B 7.2/ 3.69.5P 7.2/ 4.6

4.5P 6.9/ 2. 79. 5P 7,3/ 6.0

3.5PB 7.4/ 3.05. OB 7.2/ 3. 7

10.0PB 7.1/ 4.0

Color-Blindness 257

TABLE

Munsellbook nota-

tion

P 7/ 4B 7/ 6

10B 7/ 4PB 7/ 4

P 7/ 6

10PB 7/ 610B 7/ 6PB 7/ 6

10YR 6/105YR 6/12

Y 6/ 8Y 6/ 8

10Y 6/ 6YR 6/10

Y 6/ 610YR 6/ 8

GY 6/ 8GY 6/ 6YR 6/ 8

10YR 6/ 610R 6/10

10GY 6/1010GY 6/ 8

10R 6/ 810Y 6/ 4

YR 6/ 6Y 6/ 4

10GY 6/ 610YR 6/ 4

GY 6/ 4

10R 6/ 6YR 6/ 4

R 6/1010GY 6/4

R 6/ 810R 6/ 4

Y 6/ 2GY 6/ 2

G 6/ 6R 6/6

YR 6/ 2

R 6/ 4G 6/ 4

10RP 6/1010RP 6/ 8

10G 6/ 2

R 6/ 210RP 6/ 6

10G 6/ 610RP 6/ 4

G 6/ 4

N 6/5RP 6/ 25BG 6/ 25RP 6/ 45RP 6/ 65RP 6/ 8

4. Deuteranopic arrangement—Continued

Deuteran-opic re-

flectance,Wd = Y

0.4457.4436

.4526.

.4743

. 4381

. 4365

.4576,4556

.3595

.3241

.3242

.3145

.3278

.3350

.3179

.3457

.3238

.3200

.3274

.3392

.3243

.3032

.3224

.3345

.3291

.3221

.3100

.3168

.3149

.3217

.3384

.3113

.3236

.3101

.3236

.3262

.3211

.3245

.3040

.3308

.3124

.3313

.3151

. 3210

.3248

.3032

.3205

.3240

.3538

.3239

.3458

.3032

.3169

.3429

.3454

.3345

. 3349


coordinate,wd

0.3961.3958. 3954.3885. 3765

. 3737

. 3709

.3687

.8349

.8401

. 8313

.8289

.7980

.7855

.7817

.7653

.7457

.7246

.7192

.7150

.7068

.7025

.6692

.6466

.6411

.6410

.6385

.6299

.6173

.6151

.5995

.5751

.5628

.5598

.5436

.5432

.5317

.5239

.5237

.5200

.5155

.5065

.5018

.4964

. 4875

.4836

.4806

.4792

.4756

.4700

.4677

.4586

.4548

.4524

.4504

.4503

.4438

]Munsell renotations

Deuteranopic

5 P B5 P B5 P B5 P B5 P B

5 P B5 P B5 P B

5Y5Y5Y5Y5Y5Y

5Y5Y5Y5Y5Y

5Y5Y5Y5Y5Y5Y

5Y5Y5Y5Y5Y

5Y5Y5Y5Y5Y5Y

5Y5Y5Y5Y5Y

5Y5Y5Y5Y5Y

5Y5Y5Y5Y5Y

N5 P B5 P B5 P B5 P B5 P B

7.1/7.1/7.2/7.3/7.0/

7.0/7.2/7.2/

6.5/6.2/

6.1/6.1/6.2/

6.3/

6.2/6.4/6.2/6.2/6.2/

6.3/6.2/6.0/6.2/6.3/6.2/

6.2/6.1/6.1/6.1/6.2/

6.3/6.2/6.2/6.1/6.2/6.2/

6.2/6.2/6.0/6.2/6.1/

6.3/6.1/6.2/6.2/6.0/

6.2/6.2/6.4/6.2/6.4/

6.0/6.1/6.4/6.4/6.3/6.3/

3.83.83.84.44.9

5.05.25.4

8.88.68.48.27.77.4

7.27.06.55.95.9

5.85.65.44.84.34.2

4.24.13.93.63.6

3.32.62.42.31.91.9

1.71.71.51.41.3

1.11.00.90.70.6

0.60.60.50.50.3

0.20.20.30.30.7

Normal

5. OP 7.1/ 4.85. OB 7.1/ 4. 79. OB 7. 2/ 4.0

4.0PB 7.3/ 4.55. 5P 7.0/ 6.4

10.0PB 7.0/ 5.39. 5B 7. 2/ 5. 7

4.0PB 7.2/ 5.6

10.0YR 6.5/ 9.86.0YR 6.2/11.5

5. 5Y 6. 2/ 8.35. 5Y 6.1/ 8.19. 5Y 6.2/ 7. 4

6.0YR 6.3/ 9. 8

5. OY 6. 2/ 7.29. 5YR 6.4/ 8.04. OG Y 6. 2/ 7. 25.0GY 6. 2/ 6. 75.0YR 6.2/ 8.3

9. 5YR 6.3/ 6. 70. 5YR 6. 2/10.19. OGY 6.0/ 8. 79.0GY 6. 2/ 7. 70.5YR 6.3/ 8.210. OY 6. 2/ 4.1

4.5YR 6.2/ 6.04. 5Y 6.1/ 4.0

10.0GY 6.1/ 6. 70. 5Y 6.1/ 4.1

5.0GY 6. 2/ 4.0

0. 5YR 6.3/ 6. 54.0YR 6.1/4.0

4. OR 6.2/9.70. 5G 6.1/ 4. 44. OR 6. 2/ 8.19. OR 6. 2/ 4. 2

4. OY 6. 2/ 1. 75.0GY 6. 2/ 1. 7

6.0G 6.0/ 7.43. 5R 6. 2/ 6.3

4. 5YR 6.1/ 2.0

4. 5R 6.3/ 4. 5

6. OG 6.1/ 4.69. 5RP 6. 2/ 8.89.0RP 6. 2/ 7.0

6. OG 6.0/ 2.4

4. OR 6. 2/ 2.39. ORP 6. 2/ 5. 51.0BG 6.4/ 6.08. 5RP 6. 2/ 4. 02.0BG 6.4/ 4.5

N 6.0/4. ORP 6.1/ 2.25.0BG 6.4/ 2.44. 5RP 6. 4/ 4. 24. 5RP 6.3/ 5. 65. ORP 6.3/ 7.3

TABLE 4. Deuteranopic arrangement—Continued

Munsellbook nota-

tion

BG 6/ 4BG 6/ 6RP 6/1010P 6/ 4 -

10BG 6/ 4

P 6/ 2B 6/ 2

PB 6/ 210P 6/ 6

10BG 6/ 6

B 6/ 4P 6/ 4

10P 6/ 810B 6/ 4PB 6/ 4

10PB 6/ 4B 6/ 6

10B 6/ 6P6/ 6

10PB 6/ 6

PB 6/ 6P 6/ 8

PB 6/ 810PB 6/ 8

5YR 5/10

10YR 5/ 8Y 5/ 6

GY 5/ 8YR 5/ 8

10Y 5/ 610R 5/10

10YR 5/ 610R 5/ 8GY 5/ 6

10GY 5/ 8YR 5/ 610Y 5/ 4

Y 5/ 410GY 5/ 6

R 5/1210YR 5/ 4

10R 5/ 6GY 5/ 4

R 5/10

YR 5/ 4R 5/ 8

10R 5/ 410GY 5/ 4

R 5/ 6

G 5/8Y 5/ 2

GY 5/ 2G 5/ 6R 5/ 4

YR 5/ 2G 5/ 4

1 \ An ̂ A|*n«

-L/cuieian-opic re-

flectanceWd=Y

0.3425.3473.3389.3238.3316

.3238

.3234

.3432

.3307

.3375

.3250

.3301

.3245

.3415

.3589

.3394

.3128

.3320

.3179

.3161

.3404

.3157

.3329

.3200

.2056

.2099

.1984

.2100

.2081

.2250

.1977

.2121

.2175

.2066

.1910

.1981

.2224

.1987

.2141

.1938

.2048

. 2073

.2070

.2128

.1905

.1963

.2028

.2025

.1998

.1875

.2117

.2097

.1869

.1915

.1927

.1856


coordinate,ivd

0.4431.4379.4358.4176.4163

.4126

.4109

.4007

.4005

.3995

.3858

.3840

.3820

.3777

.3753

.3729

.3586

.3557

.3545

.3455

. 3447

.3316

.3260

.3210

.8101

.8054

.7817

.7743

.7537

.7535

.7446

.7132

.6976

.6931

.6963

.6895

.6776

.6657

.6645

.6608

.6554

.6472

.6338

.6224

.6173

.5988

.5774

.5766

.5594

.5521

.5412

.5376

.5348

.5275

.5234

.5195

Munsell renotations

Deuteranopic

5PB 6.4/ 0.85PB 6.4/ 1.15PB 6.3/ 1.15PB 6\ 2/ 2. 25PB 6.3/ 2.3

5PB 6. 2/ 2. 55PB 6. 2/ 2.65PB 6. 4/ 3.1

5PB 6. 2/ 3.15PB 6.3/ 3.2

5PB 6. 2/ 3.95PB 6. 2/ 4.05PB 6. 2/ 4.15PB 6.3/ 4.55PB 6. 5/ 4. 6

5PB 6.3/ 4.65PB 6.1/ 5.35PB 6.3/ 5. 45PB 6. 2/ 5. 45PB 6.1/ 5.9

5PB 6.3/ 6.15PB 6.1/ 6. 75PB 6.3/ 7. 45PY 6. 2/ 7. 4

5Y 5.1/ 6. 9

5Y 5.1/ 6.85Y 5.0/ 6.15Y 5.1/ 6.15Y 5.1/ 5. 7

5Y 5.3/ 5.85Y 5.0/ 5. 75Y 5. 2/ 5.05Y 5. 2/ 4. 75Y 5.1/ 4. 6

5Y 4.9/ 4. 45Y 5.0/ 4. 45Y 5.3/ 4. 45Y 5.0/ 4.05Y 5. 2/ 4.0

5Y 5.0/ 3.85Y 5.1/ 3.85Y 5.1/ 3. 65Y 5.1/ 3.45Y 5. 2/ 3.3

5Y 4. 9/ 3.15Y 5.0/ 2. 75Y 5.1/ 2.35Y 5.0/ 2. 35Y 5.0/ 2.0

5Y 4. 9/ 1. 85Y 5. 2/ 1. 75Y 5.1/ 1.65Y 4.9/ 1. 55Y 4. 9/ 1.4

5Y 4. 9/ 1.35Y 4. 9/ 1. 2

Normal

5.5BG 6.4/ 4.15.5BG 6.4/ 5.24.5RP 6.3/ 8.510. OP 6. 2/ 4. 6

10.0BG 6/3 4.1

4. 5P 6. 2/ 3.07. 5B 6. 2/ 3.0

5.0PB 6.4/ 3.29. 5P 6. 2/ 6. 2

10.0BG 6.3/ 5.8

6. 5B 6. 2/ 4. 54. OP 6. 2/ 4. 99. OP 6. 2/ 8.0

10. OB 6.3/ 4.65. OPB 6. 5/ 4. 7

0. 5P 6.3/ 4.85. 5B 6.1/ 6. 49. OB 6.3/ 6.34. 5P 6. 2/ 7.1

10. OPB 6.1/ 6. 3

5. OPB 6.3/ 6. 25. OP 6.1/ 9.1

5. OPB 6.3/ 7.40. 5P 6. 2/ 8.0

5. 5YR 5.1/ 9.00. 5Y 5.1/ 7. 66. OY 5.0/ 6.0

5.0GY 5.1/ 7.15. 5YR 5.1/ 7. 7

10. OY 5.3/ 5. 810. OR 5.0/ 9.9

10.0YR 5. 2/ 5. 70. 5YR 5. 2/ 8. 75.0GY 5.1/ 5.4

9. 5GY 4.9/ 7.85.0YR 5.0/ 6. 20. 5GY 5.3/ 4.4

5. OY 5.0/ 3.99. 5GY 5. 2/ 7.1

5. 5R 5.0/12.810.0YR 5.1/ 4.4

10. OR 5.1/ 7.15. 0GY 5.1/ 4.1

5. CR 5. 2/10. 9

4. 5YR 4.9/ 4.64.5R 5.0/10.09. 5R 5.1/ 4. 9

10. OGY 5.0/ 4.34. OR 5. 0/ 8.0

5. OG 4. 9/ 8. 2

4. 5Y 5. 2/ 1. 75.0GY 5.1/ 2.0

5. OG 4.9/ 6.64. OR 4.9/ 5.3

4.0YR 4. 9/ 2.1

5. OG 4.9/ 4.8


TABLE

Munsellbook nota-

tion

10RP 5/1010RP 5/ 810RP 5/ 6

R 5/ 2G 5/ 2

10RP 5/ 410G 5/ 610G 5/ 4

RP 5/ 2N 5/

BG 5/ 2RP 5/ 4RP 5/6

5RP 5/10RP 5/8BG 5/ 4BG 5/ 6

P 5/ 2

10P 5/ 4B 5/ 2

10BG 5/ 410P 5/ 6PB 5/ 2

10P 5/ 8P5/ 4

10BG 5/ 6B 5 / 4

10B 5/ 4

PB 5/ 410P 5/10

10PB 5/ 4P 5 / 6B 5 / 6

10B 5/ 6PB5/ 6

10PB 5/ 6P 5 / 8

PB5/ 8

10PB 5/ 8P5/10

PB 5/1010PB 5/10

5YR 4/ 810R 4/1010R 4/ 8

10 YR 4/ 4R4/14R4/14

Y R 4 / 6Y 4 / 4R4/12

10Y 4/ 410R 4/ 6

GY4/ 6YR4/ 4

R4/10


Deuteran-opic re-

flectance,Wd=Y

0.2180. 2111.2191

.1954

.1888

.2260

.2013

.2047

.2138

.1906

.2077

.2110

.2099

.2301

.2206

.2112

.2097

.1959

.2143

.1917

.2062

.2129

.2087

.2174

.1934

.2160

. 1959

.2134

.2170

.2226

.2180

.1965

.1940

.2132

. 2241

.2149

.2107

.2345

.2126

.2039

.2263

. 2014

.1354

.1493

.1428

. 1318

.1334

.1335

.1445

.1243

.1360

.1385

.1424

.1249

.1416

.1303


coordinate,Wd

0. 5156.5086.4932

.4891

.4835

.4814

.4767

.4707

. 4552

.4540

.4501

.4458

.4410

.4395

.4356

.4323

.4250

.4101

.4089

.4037

.3998

.3922

.3891

.3737

.3697

.3687

.3618

.3616

.3599

.3576

.3528

.3424

.3333

.3292

.3299

.3223

.3154

. 3036

.2938

.2893

.2871

.2757

.7407

.7234

.7112

.7063

.7081

.7034

.7032

.6871

.6831

.6733

.6726

.6661

.6556

.6307

Munsell renotations

Deuteranopic

5Y 5. 2/ 1. 2

5Y 5. 2/ 1.05Y 5. 2/ 0. 7

5Y 5.0/ 0. 65Y 4.9/ 0. 55Y 5.3/ 0. 5

5Y 5.0/ 0. 45Y 5.1/ 0. 2

5PB 5. 2/ 0.15PB 4. 9/ 0. 25PB 5.1/ 0.35PB 5 2 / 0 45PB 5.1/ 0. 7

5PB 5.3/ 0.85PB 5.2/ 1.05PB 5. 2/ 1.15PB 5.1/ 1.45PB 5.0/ 2.0

5PB 5.2/ 2.25PB 4.9/ 2.25PB 5.1/ 2. 55PB 5. 2/ 2. 95PB 5.1/ 3.0

5PB 5. 2/ 3. 85PB 5.0/ 3.85PB 5. 2/ 4.05PB 5.0/ 4.25PB 5. 2/ 4. 3

5PB 5. 2/ 4. 55PB 5.3/ 4. 65PB 5. 2/ 4. 75PB 5.0/ 5.15PB 5.0/ 5. 5

5PB 5. 2/ 5.85PB 5.3/ 6.15PB 5. 2/ 6. 35PB 5.1/ 6.65PB 5.4/ 7. 5

5PB 5. 2/ 7.85PB 5.1/ 8.15PB 5.3/ 8. 45PB 5.0/ 8.8

5Y 4. 2/ 5.85 Y 4.4/ 4.65Y 4.3/ 4.35Y 4. 2/ 4. 25Y 4. 2/ 4. 25Y 4. 2/ 4. 2

5Y4.4/ 4.25Y 4.1/ 3. 75Y 4. 2/ 3. 85Y 4.3/ 3. 75Y 4.3/ 3. 7

5Y 4.1/ 3. 45Y 4.3/ 3. 45Y 4. 2/ 3.0

Normal

10.0RP 5.2/10.3

10.0RP 5. 2/ 8.610.0RP 5. 2/ 6. 6

4. OR 5.0/ 2. 86. 5G 4.9/ 2.4

10.0RP 5. 3/ 4. 2

1.0BG 5.0/ 7.00.5BG 5.1/ 4.6

5.0RP 5. 2/ 2. 35.0PB 4. 9/ 0.14.5BG 5.1/ 2.55.0RP 5.2/ 4.34. 5RP 5.1/ 6. 2

5. 5RP 5.3/ 9. 74. 5RP 5. 2/ 8.05.5BG 5.2/ 4.45.0BG 5.1/ 6.4

5. OP 5.0/ 2. 5

1. 0RP 5. 2/ 4.96. 5B 4.9/ 2. 60. 5B 5.1/ 4.4

1.0RP 5. 2/ 6. 75.0PB 5.1/ 3.1

1.0RP 5. 2/ 8.64. 5P 5.0/ 4. 71. OB 5.2/ 6. 55. 5B 5.6/ 5.1

10. OB 5. 2/ 4. 6

4.5PB 5.2/ 4.40. 5RP 5.3/10. 4

10.0PB 5. 2/ 5.05. OP 5. 0/ 6.85. OB 5. 0/ 6.8

9.5B 5.2/ 6.34.0PB 5.3/ 6. 2

10. OPB 5,2/ 6.8

5. OP 5.1/ 8.94. OPB 5.4/ 7. 9

10.0PB 5.2/ 8.45. OP 5.1/10. 9

3. 5PB 5. 3/ 8.610. OPB 5.0/ 9. 6

6.0YR 4. 2/ 6.39. 5R 4. 4/ 9.0

10. OR 4.3/ 8. 410.0YR4.2/ 4.6

5. 5R 4. 2/13. 25. 5R 4. 2/13. 2

5.0YR4.4/ 5.85. OY 4.1/ 3. 65. OR 4. 2/12. 6

10. OY 4.3/ 3. 710. OR 4.3/ 7.3

5. 0GY 4.1/ 4.05.0YR4.3/ 4.6

4. 5R 4. 2/10. 8

TABLI

Munsellbook nota-

tion

10 GY 4/ 6GY4/4

R4/ 810R 4/ 4

10GY 4/ 4R4/ 6Y 4 / 2

YR4/ 2GY4/2

R4/ 4G 4/ 4

10RP 4/10

R 4/ 210RP 4/ 6

G 4/ 210RP 4/ 810RP 4/ 4

103 4/ 4N 4/

RP 4/ 2BG 4/ 2RP 4/ 4

BG 4/4RP 4/ 6RP 4/ 8RP 4/10BG 4/ 6

5RP 4/125P 4/ 25B 4/ 2

10BG 4/ 410P 4/ 4

PB 4/ 210BG 4/ 6

10P 4/ 6P 4/ 4B 4/ 4

10B 4/ 410P 4/ 8PB 4/ 4

10PB 4/ 4P 4/ 6

10P 4/10B 4/ 6

PB 4/ 6P 4/ 8

10B 4/ 6

B 4/810PB 4/ 6

10B 4, 8P 4/10

PB 4/ 8

10PB 4/ 8P 4/12

10PB 4/10PB 4/10

4. Deuteranopic

ueuceran-opic re-

Wd=Y

0.1355.1313

.1306

.1348

.1337

.1247

.1419

.1268

.1357

. 1236

.1291

. 1358

.1230

.1262

.1282

.1332

.1277

.1283

.1209

.1445

.1382

.1418

.1413

.1406

.1341

.1359

.1354

.1396

. 1248

.1374

.1290

.1428

.1313

.1349

.1407

.1289

.1447

. 1299

.1406

.1355

.1288

.1240

.1331

.1287

.1364

.1278

.1316

. 1172

.1321

.1292

.1292

.1387

. 1291

.1252

.'1224

. 1416


coordinate,Wd

0.6279.6173

.6111

.6007

. 5716

.5663

.5534

.5484

. 5357

.5257

.5218

. 5024

.4963

. 4903

.4884

.4876

.4754

.4731

.4526

.4474

.4424

.4332

.4296

.4230

.4172

. 4127

.4114

.4076

.4028

.4005

. 4002

.3969

.3888

.3721

.3718

.3653

.3557

.3527

. 3519

.3441

.3377

.3313

. 3291

.3144

.3071

.3020

.3014

.2991

.2985

.2831

.2828

.2783

.2685

. 2504

. 2492

. 2560

arrangement—Continued

Munsell renotations

Deuteranopic

5Y 4. 2/ 2.95Y 4. 2/ 2. 7

5Y 4. 2/ 2. 65Y 4. 2/ 2. 55Y 4. 2/ 2.05Y 4.1/ 1. 95Y 4.3/ 1. 7

5Y 4.1/ 1. 55Y 4. 2/ 1. 45Y 4.1/ 1. 25Y 4.1/ 1.15Y4.2/0.8

5Y 4.1/ 0. 75Y 4.1/ 0. 65Y 4.1/ 0. 65Y 4. 2/ 0. 55Y 4.1/ 0. 3

5Y 4.1/ 0.35PB 4.0/ 0.15PB 4. 4/ 0. 35PB 4. 3/ 0.45PB 4. 3/ 0. 8

5PB 4. 3/ 0. 95PB 4.3/ 1.15PB 4. 2/ 1. 35PB 4.2/ 1.55PB 4. 2/ 1. 5

5PB 4. 3/ 1. 75PB 4.1/ 1.85PB 4.3/ 1.95PB 4.1/ 1.95PB 4. 3/ 2.1

5PB 4. 2/ 2. 45PB 4. 2/ 3. 05PB 4. 3/ 3.15PB 4.1/ 3. 25PB 4. 4/ 3. 7

5PB 4. 2/ 3. 75PB 4. 3/ 3. 95PB 4. 2/ 4. 25PB 4.1/ 4. 45PB 4.1/ 4. 6

5PB 4. 2/ 4. 85PB 4.1/ 5. 45PB 4. 2/ 5. 95PB 4.1/ 5. 95PB 4. 2/ 6. 0

5PB 4. 0/ 5. 95PB 4. 2/ 6. 25PB 4.1/ 7. 05PB 4.1/ 6. 95PB 4. 3/ 7.3

5PB 4.1/ 7. 65PB 4.1/ 8. 65PB 4.0/ 8. 65PB 4. 4/ 8. 9

Normal

10.0GY4. 2/ 5.45.0GY4.2/ 3.2

4. 5R 4. 2/ 9. 40. 5YR 4. 2/ 4. 7

LOG 4. 2/ 4.14.5R4.1/ 6.85. 5Y 4. 3/ 1. 7

4.0YR 4.1/ 2.35. 5GY 4. 2/ 1. 7

3. 5R 4.1/ 4. 75.0G4.1/ 4.9

9. 5RP 4. 2/ 9. 5

. 4. OR 4.1/ 2. 69. 5RP 4.1/ 6.4

6.0G 4.1/ 2.49.0RP 4.2/ 8.29.0RP 4.1/ 4.1

0.5BG 4.1/ 4.55. OPB 4. 0/ 0.14. 0RP 4.4/ 2.15.5BG 4.3/ 2.54. ORP 4. 3/ 4. 4

5.5BG 4.3/ 4.04. 5RP 4. 3/ 6. 44. 5RP 4. 2/ 7. 94.5RP 4.2/ 9.45. 5BG 4.2/ 6.0

5. ORP 4. 3/10. 75. OP 4.1/ 2. 25. OB 4. 3/ 2. 7

9.5BG 4.1/ 4.00. 5RP 4. 3/ 4. 5

5. OPB 4. 2/ 2. 510.0BG 4.2/ 5.70. 5RP 4. 3/ 6. 6

5. OP 4.1/ 4. 26 OB 4. 4/ 4. 6

0. 5PB 4. 2/ 4.10. 5RP 4. 3/ 8. 55. OPB 4. 2/ 4.3

10. OPB 4.1/ 4. 65. OP 4.1/ 6.1

0. 5RP 4.2/10.45. 5B 4.1/ 6. 4

4. 5PB 4. 2/ 6. 05. OP 4.1/ 8. 2

0.5PB 4.2/ 6.3

6. 5B 4. 0/ 6. 910. OPB 4. 2/ 6. 6

10. OB 4.1/ 7.35. OP 4.1/10.1

4. 5PB 4. 3/ 7. 4

10. OPB 4.1/ 8. 55. 5P 4.1/12. 6

10. OPB 4.0/ 9. 74. OPB 4.4/ 8. 9

Color-Blindness 2S9

TABLE

Munsellbook nota-

tion

5YR 3/ 410R 3/ 6

R 3/1010YR 3/ 210GY 3/ 4

R 3/ 810R 3/ 4GY 3/ 410Y 3/ 2

R 3/6

YR 3/ 2YR 3/ 2GY 3/ 2

R 3/ 4G 3/4Y 3/ 2

G 3/ 2R 3/ 2

10RP 3/ 810RP 3/ 6

10G 3/ 4

10RP 3/ 410RP 3/10

N 3/RP 3/ 2BG 3/ 2

RP 3/ 4R P 3/ 6BG 3/ 4RP 3/8RP 3/10

BG 3/ 6P 3/ 2B 3/ 2

10BG 3/ 4PB 3/ 2

10P 3/ 410BG 3/ 6

B 3/ 410P 3/ 6

P 3/ 4

10B 3/ 45PB 3/ 410P 3/ 8

B 3/ 610PB 3/ 4

P 3/610P 3/1010B 3/ 6PB 3/ 6

10PB 3/ 6

P 3/810B 3/ 8

10PB 3/ 8PB 3/ 8

P 3/10


Deuteran-opic re-

flectance,Wd=Y

0.0783.0786.0744.0696.0756

.0743

.0741

.0739

.0788

.0829

.0698

.0701

.0748

. 0734

.0803

.0689

.0703

.0716

.0698

.0712

.0754

.0658

.0735

.0651

.0654

.0727

.0675

.0664

. 0716

.0706

.0743

.0767

.0736

.0715

.0778

.0689

.0731

.0727

.0700.0722.0705

.0708

.0699

.0700

.0802

.0713

.0744

.0648

.0765

.0749

.0711

.0759

.0812

.0724

.0768

.0769


coordinate,Wd

0.6552.6380.6332.6231.6102

.6055

.5961

.5960

.5685

.5647

.5602

.5577

.5533

.5506

.5407

.5362

.4989

.4979

.4847

.4821

.4736

.4703

.4640

.4511

.4404

. 4327

.4299

.4229

.4180

.4060

.3975

.3970

.3870

.3854

.3788

.3710

.3699

. 3475

.3393

.3327

.3278

.3236

.3179

.3097

.3047

.3026

.2950

.2767

.2840

.2803

.2750

.2681

.2542

.2525

.2498

.2342

Munsell renotations

Deuteranopic

5Y 3.3/ 3.05Y 3.3/ 2.85Y 3.2/ 2. 75Y 3.1/ 2. 55Y 3.2/ 2.3

5Y 3.2/ 2.25Y 3.2/ 2.15Y 3.2/2.15Y 3.3/ ]5Y 3.4/ ]

5Y 3.1/ ]5Y 3.1/ ]5Y 3.2/ ]5Y 3. 2/ 1

1.7L.7

.61.5.4

L.45Y 3.3/ 1.35Y 3.1/ 1.2

5Y 3.1/ 0.65Y 3.1/ 0.65Y 3.1/ 0. 55Y 3.1/ 0.45Y 3. 2/ 0.3

5Y 3.0/ 0.35Y 3.2/ 0.1

5PB 3.0/ 0.15PB 3.0/ 0.35PB 3. 2/ 0.6

5PB 3.0/ 0.65PB 3.0/ 0.85PB 3.1/ 0.95PB 3.1/ 1. 25PB 3.2/ 1. 5

5PB 3.2/ 1.55PB 3. 2/ 1.85PB 3.1/ 1.85PB 3.3/ 2.05PB 3.1/ 2. 2

5PB 3. 2/ 2.35PB 3.2/ 2.95PB 3.1/ 3.15PB 3. 2/ 3.45PB 3.1/ 3. 5

5PB 3.1/ 3.65PB 3.1/ 3.85PB 3.1/ 4.15PB 3.3/ 4. 55PB 3.1/ 4. 5

5PB 3. 2/ 4.85PB 3.0/ 5.25PB 3.2/ 5.35PB 3. 2/ 5. 55PB 3.1/ 5. 5

5PB 3. 2/ 6.05PB 3.3/ 6. 95PB 3. 2/ 6. 85PB 3.2/ 7.05PB 3. 2/ 7. 8

Normal

5.0YR 3.3/ 4.110. OR 3.3/ 5.45. OR 3. 2/ 8.3

10.0YR 3.1/ 2. 710.0GY 3. 2/ 4. 5

5. OR 3.2/ 7.410. OR 3.2/ 4.1

5.0GY 3.2/ 2.60.5GY 3.3/ 1.8

4. 5R 3.4/ 6. 2

5.0YR 3.1/ 2.05.0YR 3.1/ 2.14. 5GY 3. 2/ 1.9

5. OR £2/ 4.64. OG 3.3/ 4.86.0Y 3.1/ 1.1

5. OG 3.1/ 2. 73. 5R 3.1/ 2.1

9.0RP 3.1/ 7.09. ORP 3.1/ 5.610. OG 3.2/ 4.7

9. ORP 3.0/ 3.48. 5RP 3. 2/ 8. 5

2. 5P 3.0/ 0. 24. 5RP 3.0/ 1.95.0BG 3.2/ 2.8

5. ORP 3.0/ 3. 75. ORP 3.0/ 5. 25.0BG 3.1/ 4.15. ORP 3.1/ 6.85. ORP 3.2/ 8.4

6.0BG 3.2/ 5.35. OP 3.2/ 2. 25. 5B 3.1/ 2.3

9.5BG 3.3/ 4.35. OPB 3.1/ 2.1

10. OP 3. 2/ 4. 59.5BG 3.2/ 5.8

4. 5B 3.1/ 4. 29. OP 3. 2/ 6.35. OP 3.1/ 4. 5

9. 5B 3.1/ 3.95. OPB 3.1/ 3.910. OP 3.1/ 8.35. OB 3.3/ 5.9

10. OPB 3.1/ 4. 7

4. 5P 3. 2/ 6.49. OP 3.0/ 9.89. 5B 3. 2/ 5.6

5. OPB 3.2/ 5.610. OPB 3.1/ 6.1

5. OP 3. 2/ 8.49. OB 3.3/ 7.1

10. OPB 3. 2/ 7. 44. 5PB 3. 2/ 7.0

5. OP 3.3/11. 2

TABLE

Munsellbook nota-

tion

PB 3/10PB 3/12

10PB 3/10

5GY 2/ 210Y 2/ 2

Y 2/ 210YR 2/ 2

YR 2/ 2

10GY 2/ 210R 2/ 2

R 2/4R 2/ 6R 2/ 2

G 2/ 210G 2/ 2

N 2/10RP 2/ 4

RP 2/ 2

BG 2/210RP 2/ 6

BG 2/ 410BG 2/ 2

RP 2/ 4

B 2/ 2RP 2/ 6

P 2/ 2PB 2/ 210B 2/ 2

10P 2/ 4P 2/ 4

10P 2/ 610PB 2/ 4

PB 2/ 4

10PB 2/ 6P 2/6

PB 2/ 6


Deuteran-

opic re-

0.0844.0802.0693

.0461

.0484

. 0472

.0505

.0439

.0440

.0458

. 0384

.0461

.0400

.0373

.0407

.0300

.0395

.0386

.0379

.0416

.0395

.0455

.0411

.0381

.0440

.0351

.0353

.0390

.0370

.0358

.0377

.0380

.0385

* .0358.0346.0405


coordinate,Wd

0.2323.2119.1960

.5595

.5589

.5579

.5519

.5420

.5399

.5344

.5168

.5151

.4878

.4850

.4678

.4505

.4458

.4362

.4351

.4333

.4180

.4070

.4045

.3952

.3790

.3506

.3388

.3353

.3220

.3102

.2957

.2770

.2715

.2660

.2659

. 2446

Munsell renotations

Deuteranopic

5PB 3.4/ 8.45PB 3. 3/ 9. 45PB 3V1/ 9.7

5Y 2. 5/ 1. 65Y 2. 6/ 1. 45Y 2. 5/ 1. 45Y 2. 6/ 1.35Y 2.4/ 1. 2

5Y 2. 4/ 1.15Y 2. 5/ 1.05Y 2. 3/ 0. 85Y 2. 5/ 0. 85Y 2.3/0.5

5Y 2. 2/ 0.45Y 2.3/ 0. 2

5PB 2.0/ 0.15PB 2.3/ 0.15PB 2.3/ 0.3

5PB 2. 2/ 0. 35PB 2. 4/ 0. 45PB 2.3/ 0. 75PB 2. 5/ 1. 05PB 2. 4/ 1.0

5PB 2. 2/ 1. 35PB 2.4/ 1. 75PB 2.1/ 2. 25PB 2. 2/ 2. 55PB 2.3/ 2. 7

5PB 2. 2/ 3.05PB 2. 2/ 3. 35PB 2. 2/ 3. 75PB 2. 2/ 4. 65PB 2.3/ 4. 7

5PB 2. 2/ 4. 65PB 2.1/ 4. 65PB 2.3/ 5. 8

Normal

4. 5PB 3. 4/ 8. 54. OPB 3.3/ 9.4

10. OPB 3.1/10. 6

5. 5GY 2. 5/ 2. 210. OY 2. 6/ 1. 65. OY 2. 5/. 1. 4

7. 5YR 2. 6/ 1. 64. 5YR 2. 4/ 1.8

9. 5GY 2.4/ 2. 58. 5R 2. 5/ 2. 64. OR 2. 5/ 3. 83. OR 2. 5/ 4. 83. 5R 2.3/ 2. 2

7. OG 2. 2/ 2.410. OG 2.3/ 3.1

5. OP 2.0/ 0. 28. ORP 2.3/ 3. 76. ORP 2.3/ 2.3

4.5BG 2.2/ 2.58. ORP 2. 4/ 5. 65.0BG 2.3/ 3.77. 0BG 2. 5/ 3.15. ORP 2.4/ 4. 6

2. OB 2. 2/ 2. 24. ORP 2.4/ 5.9

5. 5P 2.1/ 2. 94. 5PB 2. 2/ 2. 6

8. 5B 2. 2/ 3.1

9. OP 2. 2/ 5.35. OP 2. 2/ 4. 69. OP 2. 2/ 6. 8

10. OPB 2. 2/ 4. 84. OPB 2.3/ 4.8

10. OPB 2. 2/ 5. 55. OP 2.1/ 6.8

4. OPB 2.3/ 5. 9

Munsellbook

notation

N 9

10BG 8/ 25B8/ 2

10B 8/ 25PB 8/ 2

10PB 8/ 2

10Y 8/ 85GY 8/ 85GY 8/ 610Y 8/ 65Y8/ 6

TABLE 5

Protanopicreflectance,0.9733 Wp

0.7244

.6464

.6391

.6732

.6543

.6608

.5773

.5991

.5914

.5817

.5451

Protanopic arrangement

Protanopicchroma-

ticity coor-dinate, wp

0.4708

.4705

.4511

. 4317

.4267

.4205

.7889

.7505

.6659

.6657

.6609

Munsell renotations

Protanopic

5Y 8. 7/ 0. 2

5Y8.3/0.25PB8.3/ 1.35PB 8.4/ 2.85PB 8.3/ 3. 25PB 8.4/ 3. 5

5Y 7.9/ 9.35Y 8.0/ 8.35Y 8.0/ 5.95Y 8.0/ 5. 85Y 7. 7/ 5. 7

Normal

7.5Y 8. 7/ 0.1

5.0BG8.2/ 1.94. OB 8.2/ 2. 2

1. OPB 8.3/3.05. OPB 8.3/ 3. 27. 5PB 8.3/ 3.4

if

0.5GY 8.1/ 9.14. 5GY 8.1/ 8. 75. 5GY 8.0/ 6. 20. 5GY 8.0/ 5. 74. 5Y 7.9/ 5.8


TABLE 5. Protanopic arrangement—Continued TABLE 5. Protanopic arrangement—Continued

Munsellbook

notation

10YR 8/ 610GY 8/ 6

10Y 8/ 45GY 8/ 4

10GY 8/ 4

10YR 8/ 45YR 8/ 4

5G8/65GY 8/ 2

5G8/ 4

10R 8/ 45G8/ 2

10G 8/ 25YR 8/ 25BG 8/ 2

5R8/ 4N 8 /

5R8/ 25RP 8/ 2

10RP 8/ 4

10RP 8/ 65RP 8/ 65RP 8/ 4

5B8/45P8/ 2

10P 8/ 45P8/ 4

5Y 8/12

Y 8/10Y 8/8Y 8/ 8

10GY 7/ 6

Y 8/ 410GY 7/ 4

G 7/ 6Y 8/ 2

10G 7/ 4

BG 7/ 2BG 7/ 4RP 7/4

B 7/ 210BG 7/ 4

RP 7/ 6B 7/ 4

PB 7/2B 7/ 6

10B 7/ 4

PB 7/ 410B 7/ 6

' PB 7/6

10Y 7/ 8GY 7/10GY 7/ 810Y 7/ 6GY 7/ 6

10GY 7/ 810Y 7/ 4


0.5632.5987.5873.6044.6362

.5656

.5614

.5954

.5851

.6141

.5725

.5854

.6133

.5731

.6281

.5565

.5741

.5857

.6317

.5905

.5958

.5839

.5874

.6310

.5877

.6081

. 5903

.5208

.5292

.5393

.5339

.4726

.5426

.4718

.4749

.5455

.4960

.4913

.4908

.4693

.4895

.4863

.4687

.4875

.5049

.4798

.4794

. 4942

. 4959

.4817

.4214

.4235

.4506

.4176

.4502

.4655

.4340

Protanopicchroma-


0.6134.5866.5842.5786.5545

. 5512

.5225

. 5187

.5174

.5075

.5059

.4984

.4943

.4937

.4803

.4772

.4764

.4698

.4654

.4662

.4641

.4586

.4582

.4452

.4388

. 4316

.4054

.8848

.8501

.7579

.7525

.6222

.5818

.5631

.5299

.5156

. 4951

.4752

.4733

.4558

.4505

.4471

.4463

.4313

.4260

.4213

.4158

.4048

.3963

.3878

.8324

.8191

.7486

.7387

.6922

.6697

.6064

Munsell renotations

Protanopic

5Y 7.8/ 4.35Y 8.0/ 3.65Y 8.0/ 3. 55Y8.1/3.45Y 8. 2/ 2. 7

5Y7.9/ 2.55Y 7.8/ 1.65Y 8.0/ 1. 55Y 8.0/ 1. 55Y 8.1/ 1.3

5Y 7. 9/ 1. 25Y 8.0/ 0.95Y 8.1/ 0.85Y7.9/0.85Y 8. 2/ 0. 5

5Y 7. 8/ 0. 45Y 7.9/ 0.35Y 8.0/ 0. 2N8.2/N8.0/

5PB 8.0/ 0.15PB 8.0/ 0.65PB 8.0/ 0. 75PB8.2/ 1.85PB 8.0/ 2. 2

5PB8.1/ 2.8

5PB 8.0/ 4. 5

5Y 7.6/11.85Y 7.6/10.85Y 7. 7/ 8.35Y 7. 7/ 8. 25Y 7.3/ 4.3

5Y 7.7/ 3.45Y 7.3/ 2. 75Y 7.3/ 1.85Y 7.7/ 1.55Y 7.4/ 0. 8

5Y 7.4/ 0.35Y 7.4/ 0. 2

5PB 7.3/ 0.85PB 7.4/ 1.25PB 7. 4/ 1.4

5PB 7. 3/ 1.65PB 7.4/ 2. 55PB 7. 5/ 2.95PB 7.3/ 3.15PB 7. 3/ 3. 5

5PB 7.4/ 4.35PB 7.5/ 4.95PB 7.3/ 5. 4

5 Y 6.9/ 9. 55Y 7.0/ 9. 25Y 7.1/ 7. 55Y 6. 9/ 7.05Y 7.1/ 6.1

5Y 7. 2/ 5. 55Y 7.0/3.8

Normal

9.0YR 8.1/ 5.59.5GY 7.9/ 5.11.0GY 8.0/ 3.46.0GY8.1/ 3.6

0.5G 8.2/ 4.0

9.0YR8.0/3.44.0YR 8.0/ 3. 5

6. 5G 7.8/ 4. 76.0GY 8.0/ 1.6

5. 5G 8.0/ 3.3

10. OR 8.1/ 3. 74. 5G 7.9/ 2.15. OG 8.0/ 2. 0

4. 0YR 8.0/ 2.01.0BG8.1/ 2.0

3. 5R 8.0/ 3.62. 5GY 7.9/ 0.3

2. OR 8.1/ 2.28.0RP 8.3/ 1.99. 5RP 8.1/ 2. 7

8. 5RP 8.2/ 3.66. 5RP 8.1/ 3. 45.5RP8.1/ 2.8

4. OB 8.1/ 2.95. OP 8.0/ 2. 5

7. 5P 8. 2/ 3.5

4. 5P 8.0/ 4.8

5.5Y 7.9/12.35. 5Y 7.9/11.15. 5Y 7.9/ 8. 35. 5Y 7.9/ 8. 2

10. 0GY 7.1/ 6. 5

4.0Y 7.8/3.510. OY 7.2/ 4.1

7. OG 7.0/ 6.13. 5Y 7. 8/ 1. 6

0. 5BG 7.2/ 3.9

3.5BG 7.3/ 2.14.5BG 7.2/ 3.46.0RP 7.4/ 3.3

3.5B 7.3/2.20.5B 7.2/ 3.6

5.0RP 7.4/ 4.45. OB 7. 2/ 3. 7

3. 5PB 7.4/ 3. 05. OB 7.1/ 4. 79. OB 7.2/ 4.0

4. OPB 7.3/ 4. 59. 5B 7. 2/ 5. 7

4. OPB 7. 2/ 5. 6

10. OY 7.1/ 9.34.0GY 7.0/ 9.55.0GY 7.1/ 8. 00. 5GY 7. 0/ 6. 95. 0GY 7.1/ 6. 4

10.0GY 7.1/ 8.31. OG Y 7.1/ 3.6

Munsellbook

notation

GY 7 / 4Y 7 / 4

10YR 7/ 4

Y R 7 / 410R 7/ 6GY 7/ 2

Y 7/ 2G 7/4

10R 7/ 45YR 7/ 2

G 7/ 2R 7/ 6R 7/ 4

R 7/ 210RP 7/ 410RP 7/ 6

N 7/10RP 7/ 8

RP 7/ 2RP 7/ 810P 7/ 4

P 7/ 210P 7/ 6

10PB 7/ 410P 7/ 8

P 7/ 410PB 7/ 6

P 7/ 6

Y 7/10Y 7/ 8

10YR 7/1010YR 7/ 8

YR 7/10

Y 7/ 610GY 6/ 810YR 7/ 6

YR 7/ 810GY 6/ 6

YR 7/ 6YR 7/ 610R 7/ 8

G 6/ 6G 6/4

10G 6/ 610G 6/ 4

R 7/ 8BG 6/ 2

BG 6/4

5BG 6/ 610BG 6/ 410BG 6/ 6

B 6/ 2PB 6/ 2

B 6/410B 6/ 4

B 6/ 6PB 6/ 410B 6/ 6

Protanopiceflectance,0.9733 Wp

0.4364.4079.4296

.4016

.4036

.4261

.4359

.4613

.4122

.4183

.4371

.3999

.4012

.4336

.4154

.4213

. 4441

.3999

.4599

.4540

.4510

.4085

.4505

.4544

.4489

.4419

.4435

.4283

.3814

.3879

.3602

.3885

.3443

.3854

.3403

.3919

.3696

.3343

.3757

.3682

.3635

. 3378

.3377

.3889

.3743

.3698

.3593

.3700

.3810

.3593

.3776

.3400

.3530

.3527

.3665

.3527

.3759

.3654

Protanopicchroma-

ticity coor-dinate, Wp

0. 5973.6033.5746

.5422

.5329

.5244

.5213

.5168

.5145

.5013

.4926

.4899

.4809

.4729

.4657

.4649

.4633

.4625

.4600

.4400

.4273

.4259

.4204

.4072

.4061

.4005

.3838

.3775

.8415

.8353

.8235

.7388

.7299

.7188

.6868

.6650

.6548

.6486

.5906

.5894

.5736

. 5566

.5259

.5060

.4943

.4911

.4708

.4690

.4676

.4426

.4334

.4296

.4141

.4119

.4010

.3931

.3927

.3843

Munsell renotations

Protanopic

5Y 7.0/ 3.65Y 6.8/ 3. 55Y 7.0/ 2. 9

5Y 6.8/ 2.05Y 6.8/ 1.85Y 7.0/ 1.65Y 7.0/ 1.65Y 7. 2/ 1.4

5Y 6. 9/ 1.35Y 6.9/ 1. 05Y 7.0/ 0. 75Y 6.8/ 0. 65Y 6.8/ 0: 4

5Y 7.0/ 0. 2N 6.9/N 6.9/

5PB 7.1/ 0.15PB 6.8/ 0. 2

5PB 7. 2/ 0.45PB 7.2/ 1.95PB 7.1/ 2. 75PB 6.8/ 2. 75PB 7.1/ 3.1

5PB 7. 2/ 4.05PB 7.1/ 4. 25PB 7.1/ 4.45PB 7.1/ 5. 65PB 7.0/ 5. 8

5Y 6. 6/ 9. 55Y 6.7/9.45Y 6. 5/ 8. 75Y 6. 7/ 6. 9 '5Y 6.4/ 6. 4

5Y 6.7/ 6.45Y 6.3/ 5.35Y 6. 7/ 5. 25Y 6. 6/ 4. 75Y 6.3/ 4. 5

5Y 6. 6/ 3. 25Y 6. 5/ 3. 25Y 6. 5/ 2. 85Y 6.3/ 2.35Y 6.3/ 1. 5

5Y 6. 7/ 1.15Y 6. 6/ 0. 75Y 6. 6/ 0. 75Y 6. 5/ 0. 25Y 6. 6/ 0.1

5Y 6. 6/ 0.15PB 6. 5/ 1. 55PB 6. 6/ 2.15PB 6.3/ 2. 25PB 6.4/ 3. 2

5PB 6.4/ 3.45BP 6.5/ 4.05PB 6. 4/ 4. 55PB 6. 6/ 4. 75PB 6. 5/ 5.1

Normal

5. 5GY 7.0/ 3.84. OY 7.0/ 3. 8

9.0YR 7. 2/ 3.8

3.0YR 7.0/ 4.19. OR 7. 2/ 5. 7

5.5GY 7.0/ 1.84. OY 7.1/ 1. 66. 5G 7.0/ 4.3

8. 5R 7.2/ 4.73. 0YR 7.0/ 2.1

6. 5G 7.0/ 2.13. 5R 7.1/ 5. 73. OR 7.1/ 5. 2

2.5R 7. 2/ 2.69.5RP 7.1/ 3.59. 5RP 7. 2/ 4. 77. 5PB 7.1/ 0.19.0RP 7.1/ 5.8

6. 5RP 7.3/ 2.34. 5RP 7. 4/ 4.910. OP 7. 2/ 4.04. 5P 6.9/ 2. 79. 5P 7. 2/ 4. 6

10. OPB 7.1/ 4.09. 5P 7.3/ 6.05. OP 7.1/ 4. 8

10. OPB 7.0/ 5.35. 5P 7.0/ 6. 4

5. OY 6. 9/ 9. 76. OY 6. 9/ 9. 51.0Y 6.9/10.50. 5Y 7.1/ 8.3

5. 5YR 6. 9/10.1

4. 5Y 6. 9/ 6. 69.0GY 6.2/ 7.7

10.0YR 7.0/ 6.34.5YR 7.0/ 8.2

10.0GY 6.1/ 6. 7

3. 5YR 7.0/ 6.03.5YR 6.9/ 5.910. OR 7.0/ 7. 56. OG 6.0/ 7.46. OG 6.1/ 4. 6

1.0BG 6.4/ 6.02.0BG 6.4/ 4.5

3. 5R 7.0/ 7.05.0BG 6.4/ 2.45.5BG 6.4/ 4.1

5.5BG 6.4/ 5.210.0BG 6.3/ 4.110.0BG 6.3/ 5.8

7. 5B 6. 2/ 3.05. OPB 6.4/ 3. 2

6. 5B 6. 2/ 4. 510. OB 6.3/ 4. 65. 5B 6.1/ 6. 4

5. OPB 6. 5/ 4. 79. OB 6.3/ 6.3

Color-Blindness 261


Munsellbook

notation

10PB 6/ 4PB 6/ 6PB 6/̂ 8

10YR 6/10Y 6/ 8Y 6/ 8

10Y 6/ 6Y 6/ 6

YR 6/10GY 6/ 8

10YR 6/ 8GY 6/ 6

10GY 6/10

10YR 6/ 6YR 6/ 810Y 6/ 4

Y 6/ 4GY 6/ 4

YR 6/ 610R 6/ 8

10YR 6/ 410GY 6/ 4

10R 6/ 6

YR 6/ 4Y 6/ 2

GY 6/210R 6/ 4

5YR 6/ 2

5G 6/ 2R 6/ 6R 6/ 4R 6/ 2N 6/

10RP 6/ 610RP 6/ 410RP 6/ 8

RP 6/ 2RP 6/ 4

RP 6/ 6RP 6/ 8

P 6/ 210P 6/ 4RP 6/10

10P 6/ 6P 6/ 4

10P 6/ 8P 6/ 6

10PB 6/ 6

P 6/ 810PB 6/ 8

YR 6/1210GY 5/ 6

10R 6/1010G 5/ 6

R 6/10

R 6/ 8


0.3436.3634.3575

.3090

.2967

.2876

.3115

.2924

.2735

.3222

.3013

.3198

.3224

.3003

.2731

.3188

.2930

.3212

.2808

.2737

.2916

. 3239

. 2898

.2826

.3127

.3243

.2944

.2977

.3158

.2879

.3004

.3060

.3032

.2915

.3019

.2811

.3072

.3260

.3057

.2968

.3218

.3098

.2951

.3121

.3270

.3013

.3126

.3227

.3080

.3277

.2572

.2272

.2509

. 2292

. 2571*

.2692

Protanopicchroma-


0.3821.3659.3624

.8170

.8224

.8199

.7940

.7718

. 7544

.7499

.7449

.7299

.7206

.6953

.6871

.6400

.6317

.6211

.6153

.6060

.6055

. 5772

.5683

.5580

. 5319

.5305

.5244

.5103

.5006

.4921

.4888

.4758

.4653

.4596

.4593

.4583

.4538

.4428

.4347

.4208

.4176

.4135

.4086

.3931

.3882

.3710

.3569

.3564

.3322

.3322

.8107

.6835

.6572

.5159

.5124

.5045

Munsell renotations

Protanopic

5PB 6.4/ 5. 25PB 6. 5/ 6.35PB 6. 5/ 6. 4

5Y 6.1/ 8. 25Y 6. 0/ 8.15Y 5. 9/ 8.05Y 6.1/ 7. 75Y 5. 9/ 7.0

5Y 5.8/ 6. 55Y 6. 2/ 6. 75Y 6.0/ 6. 55Y 6. 2/ 6. 25Y 6.2/6.1

5Y 6.0/ 5.45Y 5.8/ 5.05Y 6. 2/ 4. 25Y 5. 9/ 3. 95Y 6. 2/ 3. 8

5Y 5.8/ 3. 55Y 5. 8/ 3.3

- 5Y 5. 9/ 3.35Y 6. 2/ 2.85Y 5.9/ 2. 4

5Y 5. 8/ 2. 25Y 6.1/ 1. 75Y 6. 2/ 1. 75Y 5.9/ 1.4

5Y 6.0/ 1.1

5Y 6.1/ 0.95Y 5.9/ 0.65Y 6.0/0.65Y 6.0/ 0. 2N 6.0/

5PB 5.9/ 0.45PB 6.0/ 0. 35PB 5.8/ 0.45PB 6.1/ 0.85PB 6. 2/ 1.4

5PB 6.0/ 1.85PB 6.0/ 2.65PB 6. 2/ 2.95PB 6.1/ 3.15PB 6.0/ 3.3

5PB 6.1/ 4. 45PB 6. 2/ 4. 75PB 6.0/ 5.65PB 6.1/ 6. 75PB 6. 2/ 6. 7

5PB 6.1/ 8. 45PB 6. 2/ 8. 4

5Y 5. 6/ 7. 55Y 5.3/ 4. 65Y 5. 6/ 4. 25Y 5.3/ 1.25Y 5.6/ 1.1

5Y 5. 7/ 0.9

Normal

0. 5P 6.3/ 4. 85. 0PB 6. 3/ 6. 25. 0PB 6. 3/ 7. 4

10. 0YR 6. 5/ 9. 85. 5Y 6. 2/ 8. 35. 5Y 6.1/ 8.19. 5Y 6. 2/ 7. 45. OY 6. 2/ 7. 2

6.0YR 6.3/ 9. 84.0GY 6. 2/ 7. 29. 5YR 6. 4/ 8. 05.0GY 6. 2/ 6. 79.0GY 6.0/ 8. 7

9.5YR 6.3/ 6.75.0YR 6.2/ 8.310. OY 6. 2/ 4.14. 5Y 6.1/ 4.0

5.0GY 6. 2/ 4.0

4. 5YR 6. 2/ 6.00. 5YR 6.3/ 8. 2

0. 5Y 6.1/ 4.10.5G 6.1/ 4.4

0. 5YR 6. 3/ 6. 5

4.0YR 6.1/ 4.0

4. OY 6. 2/ 1. 75.0GY 6. 2/ 1. 7

9. OR 6. 2/ 4. 2

4. 5YR 6.1/ 2.0

6. OG 6.0/ 2.43. 5R 6. 2/ 6.34. 5R 6.3/ 4. 54. OR 6. 2/ 2.3

N 6.0/

9. ORP 6. 2/ 5. 58. 5RP 6.2/ 4.09. ORP 6. 2/ 7.04. ORP 6.1/ 2.24. 5RP 6.4/ 4. 2

4.5RP 6.3/ 5.65. ORP 6.3/ 7. 3

4. 5P 6. 2/ 3.010. OP 6. 2/ 4. 6

4. 5RP 6.3/ 8. 5

9. 5P 6. 2/ 6. 24. OP 6. 2/ 4.99. OP 6. 2/ 8.04. 5P 6. 2/ 7.1

10. OPB 6.1/ 6. 3

5. OP 6.1/ 9.10. 5P 6. 2/ 8.0

6.0YR 6.2/11.59. 5GY 5. 2/ 7.10. 5YR 6. 2/10.11.0BG 5.0/ 7.0

4. OR 6. 2/ 9. 7

4. OR 6. 2/ 8.1

Munsellbook

notation

10G 5/ 4BG 5/ 6BG 5/ 4

10RP 6/10

10BG 5/ 410BG 5/ 6

10B 5/ 4PB 5/4

B 5/ 6

10PB 5/ 4lt)B 5/ 6

5PB 5/ 6PB 5/8PB 5/10

GY 5/810YR 5/ 8

Y 5/ 610Y 5/ 6

10GY 5/ 8

GY 5/ 610YR 5/ 6

10Y 5/ 4Y 5/ 4

GY 5/ 4

10YR 5/ 410GY 5/ 4

G 5/ 8G 5/ 6G 5/ 4

GY 5/ 2Y 5/ 2

YR 5/ 2G 5/ 2R 5/ 2

BG 5/ 210RP 5/ 4

N 5/10RP 5/ 6

RP 5/ 2

RP 5/ 4B 5/ 2

RP 5/ 6P 5/ 2

RP 5/ 8

PB 5/ 210P 5/ 4RP 5/10

B 5/ 410P 5/ 6

5P 5/ 410P 5/ 8

P 5/ 610P 5/10

10PB 5/ 6

P 5/810PB 5/ 810PB 5/10


0.2235.2393.2320.2660

.2276

.2493

.2315

.2294• .2252

.2219

.2393

.2426

.2606

.2567

.2112

. 1811

.1831

.2155

.2044

.2076

.1873

.2154

.1871

.2069

.1854

.2111

.2122

. 2075

.2008

.2097

.2056

.18131971_

. 1819

.2200

.2050

.1908

.1857

.2048

.1943

.2031

. 1843

.1941

.1863

.2164

.2005

.1862

.2187

. 1937

.1903

.1933

.1910

.1922

.2213

.2035

.2206

.2104

Protanopicchroma-


0.4993.4643.4623.4563

.4303

.4091

.3869

.3792

.3735

.3631

.3615

.3539

.3323

.3194

.7800

.7859

.7725

.7505

.7160

.6998

.6928

.6766

.6582

.6400

.6388

.5933

.5890

.5673

.5458

. 5443

.5406

. 5149

.5010

.4780

.4710

.4638

.4610

.4588

.4512

.4321

.4244

.4158

.4144

.4011

.4042

.3994

. 3947

.3941

. 3763

.3722

.3528

. 3420

. 3306

.3348

.3137

. 3073

.2901

Munsell renotations

Protanopic

5Y 5.3/ 0.85PB 5.4/ 0.15PB 5. 4/ 0. 25PB* 5. 7/ 0. 6

5PB 5. 3/ 1. 85PB 5. 5/ 2. 95PB 5. 4/ 4. 25PB 5.3/ 4.55PB 5.3/ 4.8

5PB 5. 3/ 5. 35PB 5.4/ 5.55PB 5.5/ 6.05PB 5.6/ 7.65PB 5. 6/ 8. 5

5Y 5. 2/ 6. 45Y 4. 8/ 6. 25Y 4. 8/ 5. 95Y 5. 2/ 5. 95Y 5.1/ 5. 2

5Y 5.1/ 4. 85Y 4. 9/ 4. 55Y 5. 2/ 4. 45Y 4. 9/ 3. 95Y 5.1/ 3. 7

5Y 4. 9/ 3. 55Y 5. 2/ 2. 85Y 5. 2/ 2. 75Y 5.1/ 2.35Y 5.0/ 1.8

5Y 5.1/ 1. 85Y 5.1/ 1. 75Y 4. 8/ 1.05Y 5.0/ 0.85Y 4. 8/ 0. 3

5Y 5. 2/ 0.15PB 5.1/ 0.15PB 4. 9/ 0. 25PB 4. 9/ 0. 35PB 5.1/ 0. 7

5PB 5.0/ 1.55PB 5.1/ 2.05PB 4. 8/ 2. 25PB 5.0/ 2.45PB 4. 9/ 2. 9

5PB 5.2/3.05PB 5.0/3.25PB 4. 9/ 3. 35PB 5. 2/ 3. 65PB 5. 0/ 4. 4

5PB 4. 9/ 4. 55PB 5. 0/ 5. 65PB 4. 9/ 6. 25PB 4.9/ 7.05PB 5.3/ 7.2

5PB 5.1/ 8. 55PB 5. 2/ 9.15PB 5.1/10. 3

Normal

0.5BG 5.1/ 4.65.0BG 5.1/ 6.45.5BG 5.2/4.49. 5RP 6. 2/ 8. 8

0. 5B 5.1/ 4. 41.0B 5.2/ 6.5

10. OB 5. 2/ 4.64. 5PB 5. 2/ 4. 4

5. OB 5.0/ 6. 8

10. OPB 5. 2/ 5. 09. 5B 5. 2/ 6.3

4. OPB 5.3/ 6. 24. OPB 5.4/ 7.93. 5PB 5. 3/ 8. 6

5. 0GY 5.1/ 7.10. 5Y 5.1/ 7.66. OY 5. 0/ 6.0

10. OY 5. 3/ 5. 89. 5GY 4. 9/ 7. 8

5. 0GY 5.1/ 5. 410. 0YR 5. 2/ 5. 70. 5GY 5.3/ 4. 4

5. OY 5.0/ 3. 95. 0GY 5.1/ 4.1

10.0YR 5.1/ 4.410. 0GY 5.0/ 4. 3

5. OG 4. 9/ 8. 25. OG 4. 9/ 6.65. OG 4. 9/ 4.8

5. OG Y 5.1/ 2.04. 5Y 5. 2/ 1. 7

4.0YR 4. 9/ 2.16. 5G 4.9/ 2.44. OR 5.0/ 2.8

4.5BG 5.1/ 2.510.1RP 5.3/ 4.2

5. OPB 4. 9/ 0.110. ORP 5.2/ 6.6

5. ORP 5. 2/ 2. 3

5. ORP 5. 2/ 4.36. 5B 4. 9/ 2.6

4. 5RP 5.1/ 6. 25. OP 5.0/ 2. 5

4. 5RP5. 2/ 8. 0

5. OPB 5.1/ 3.11.0RP 5.2/ 4.95.5RP 5.3/ 9.7

5. 5B 5. 0/ 5.11.0RP 5.2/ 6.7

4. 5P 5. 0/ 4. 71.0RP 5.2/ 8.6

5. OP 5. 0/ 6. 80. 5RP 5.3/10.4

10. OPB 5. 2/ 6. 8

5. OP 5.1/ 8. 910. OPB 5. 2/ 8. 410. OPB 5.0/ 9.6



Munsellbook

notation

P 5/10

YR 5/10YR 5/ 810R 5/10YR 5/ 6

10GY 4/ 6

10R 5/ 810R 5/ 6YR 5/ 4

10GY 4/ 4Y 4/ 2

G 4/ 410R 5/ 4

R 5/10R 5/ 8R 5/ 6

10G 4/ 4R 5/4

BG 4/ 2BG 4/ 4

10RP 5/ 8

BG 4/ 610RP 5/10

R P 4/ 210BG 4/ 4

B 4/ 2

10BG 4/ 6B 4/ 4

10B 4/ 4PB 4/ 4

B 4/ 6

5B 4/ 810B 4/ 6PB 4/ 610B 4/ 8PB 4/ 8PB 4/10

YR 4/ 8JOYR 4/ 4

10Y 4/ 4Y 4/ 4

GY 4/ 6

YR 4/ 610R 4/1010R 4/ 8YR 4/ 4GY 4/ 4

10R 4/ 610R 4/ 4

R 5/12GY 4/ 2YR 4/ 2

G 4/ 2R 4/ 4R 4/ 2N 4/

10RP 4/ 4

Protanopicreflectance,0.9733 W,

0.1950

.1634

.1698

.1445

.1668

.1443

. 1678

.1665

.1671

.1412

.1376

.1414

. 1749

.1497

.1427

.1572

.1421

.1636

.1475

. 1561

.1665

.1563

.1648

.1379

.1437

.1468

.1564

.1619

.1416

.1444

.1511

.1505

.1502

.1524

.1569

.1681

.1114

.1165

.1340

.1162

.1251

.1203

.1078

.1055

.1215

.1316

.1102

.1138

.1252

.1360

.1166

.1347

.1046

.1180

.1211

.1128

Protanopicchroma-


0. 2858

.7770

.7196

.6865

.6577

.6487

.6464

.6023

.5925

.5915

.5526

.5512

.5477

.5437

. 5271

.5064

.5054

.4950

.4652

.4609

.4561

.4533

.4526

.4425

.4330

.4230

.4139

.3882

.3790

.3649

.3561

.3433

.3363

.3339

.3238

.3095

.2913

.7072

.6860

.6720

.6784

.6724

.6599

.6514

.6265

.6242

.6203

.5661

.5638

.5429

.5343

.5075

.4909

.4827

.4597

.4513

Munsell renotations

Protanopic

5PB

5Y5Y5Y5Y5Y

5Y5Y5Y5Y5Y

5Y5Y5Y5Y5Y

5Y5YN

5PB5PB

5PB5PB5PB5PB5PB

5PB5PB5PB5PB5PB

5PB5PB5PB5PB5PB5PB

5Y5Y5Y5Y5Y

5Y5Y5Y5Y5Y

5Y5Y5Y5Y5Y

5Y5Y5Y

5PB5 P B

5. 0/10. 4

4.6/4.7/4.4/4.6/4.4/

4.7/4.6/4.6/4.3/4.3/

4.3/4.7/4.4/4.3/

5.84.94.13.73.4

3.52.72.62.41.7

1.71.71.51.2

4. 5/ 0. 9

4.3/ 0.84. 6/ 0. 64.4/4.5/4.6/

4.5/4.6/4.3/4.3/4.4/

4.5/4.6/4.3/4.4/4.4/

4.3/4.4/4.4/4.5/4.5/4.7/

3.9/3.9/4.2/3.9/4.1/

4.0/3.8/3.8/4.0/4.2/

3.9/3.9/4.1/4.2/3.9/

4.2/

0.10.4

0.50.50.81.21.6

2.03.23.54.34.9

5.35.95.96.77.69.3

4.13.83.83.73.7

3.63.43.22.92.9

2.71.81.81.51.2

0.83.8/ 0. 54.0/4.0/3.9/

0.30.10.4

Normal

5. OP

5.5YR5.5YR

10. OR5.0YR

10.0GY

0.5YR10. OR

4.5YRLOG5.5Y

5.0G9.5R5. OR4. 5R4. OR

0.5BG4. OR

5.5BG5. 5BG

10.0RP

5.5BGi 10. ORP

4.0RP9. 5BG

5. OB

10.0BG6. OB

0. 5PB5. OPB

5.5B

6.5B0.5PB4.5PB10. OB

4.5PB4. OPB

6.0YR10.0YR

10. OY5.0Y

5.0GY

5.0YR9.5R

10. OR5.0YR5.0GY

10. OR0.5YR

5.5R5.5GY4.0YR

6.0G3.5R4. OR

5. OPB9. ORP

5.1/10.9

5.1/5.1/

9.07.7

5. 0/ 9. 95.0/4.2/

5.2/5.1/4.9/4.2/4.3/

4.1/5.1/

6.25.4

8.77.14 .64.11.7

4.94.9

5. 2/10. 95. 0/10.05.0/

4.1/4.9/4.3/4.3/5.2/

4.2/

8.0

4 .55.32.54.08.6

6.05. 2/10.34.4/. 2.14.1/4.3/

4.2/4.4/4.2/4.2/4.1/

4.0/4.2/4.2/4.1/4.3/4.4/

4.2/4.2/4.3/4.1/4.1/

4.4/4.4/4.3/4.3/4.2/

4.3/

4.02.7

5.74.64.14.36.4

6.96.36.07.37.48.9

6.34.63.73.64.0

5.89.08.44.63.2

7.34. 2/ 4. 75.0/12.84.2/4.1/

4.1/4.1/4.1/4.0/4:1/

1.72.3

2.44.72.60.14 .1

Munsellbook

notation

RP 4/ 4P 4/ 2

PB 4/ 2RP 4/ 6*10P 4/ 4

RP 4/ 8RP 4/10

P 4/ 4RP 4/1210P 4/ 6

10PB 4/ 4P 4/ 6

10P 4/ 810PB 4/ 6

P 4/ 8

10P 4/1010PB 4/ 8

5P 4/1010PB 4/10

P 4/12

10GY 3/ 4G 3/ 4

10Y 3/ 2R 4/12R 4/10

R 4/ 8R 4/ 6

10G 3/ 45BG 3/ 2BG 3/ 4

10RP 4/ 6BG 3/ 6

10RP 4/ 810RP 4/1010BG 3/ 4

B 3/ 210BG 3/ 6

B 3/ 410B 3/ 4

B 3/ 6

10B 3/ 6PB 3/ 610B 3/ 8PB 3/ 8PB 3/10PB 3/12

YR 3/ 410YR 3/ 2

GY 3/ 4R 4/14R 4/14

10R 3/ 6

5GY 3/ 210R 3/ 4YR 3/ 2YR 3/ 2

Y 3/ 2

G 3/ 2R 3/ 4R 3/ 6R 3/ 2N 3/


0.1282.1234.1359.1206.1329

.1098

.1060

.1256

. 1047

.1262

.1314

.1198

.1226

.1365

.1219

.1112

.1347

.1212

.1283

.1145

.0804

.0885

.0775

.0812

.0851

.0912• .0967.0849.0791.0809

.1019

.0893

.1027

.0980

.0888

.0774

.0870

.0803

.0794

.0961

.0900

.0839

.0997

.0892

.1002

.0982

.0665

.0636

.0741

.0762

.0763

.0614

.0747

.0611

.0636

.0641

.0671

.0747

.0593

. 0630

. 0649

.0651

Protanopicchroma-

ticity coor-dinate, IV p

0.4152.4067.4035.3925. 3861

.3759

.3602

. 3654

.3465

. 3530

.3483

.3297

.3274

.3111

.2977

.2964

.2824

.2754

.2633

.2388

.6310

.5713

.5710

.5693

.5339

.5300

.5100

.5099

.4604

.4546

.4438

.4407

.4297

.4281

.4168

.4109

.3958

.3771

.3554

.3504

.3241

.3095

.3006

.2843

.2694

.2528

.6237

.6080

.6030

.5874

. 5820

.5859

.5598

.5558

.5437

.5424

.5362 .

.5207

.5041

. 5031

.4802

.4579

Munsell renotations

Protanopic

5PB 4.1/ 1.85PB 4.1/ 2. 25PB 4. 2/ 2.45PB 4.0/ 2.75PB 4. 2/ 3.1

5PB 3.8/ 3.15PB 3.8/ 3.85PB 4.1/ 4.05PB 3. 8/ 4. 55PB 4.1/ 4. 6

5PB 4.2/ 5.05BP 4.0/ 5.85PB 4.0/ 5.95PB 4. 2/ 7.1

. 5PB 4.0 /7.8

5PB 3.9/ 7.55PB 4. 2/ 9. 25PB 4.0/ 9. 35PB 4.1/10.25PB 3.9/12.1

5Y 3. 3/ 2. 85Y 3. 5/ 1. 85Y 3.3/ 1.85Y 3. 3/ 1. 85Y 3. 4/ 1. 2

5Y 3. 5/ 1.15Y 3. 6/ 0. 85Y 3. 4/ 0.8

5PB 3. 3/ 0.15PB 3.3/ 0.3

5PB 3. 7/ 0. 65PB 3. 5/ 0. 75PB 3. 7/ 1.15PB 3. 6/ 1.15PB 3. 5/ 1. 4

5PB 3. 3/ 1. 55PB 3.4/ 2.15PB 3.3/ 2.65PB 3.3/ 3.45PB 3. 6/ 3. 9

5PB 3. 5/ 5. 25PB 3.4/ 5.85PB 3. 7/ 6. 75PB 3.5/ 7.35PB 3.7/ 9.05PB 3.6/ 9.5

5Y 3.0/ 2. 65Y 3.0/ 2.35Y 3. 2/ 2.35Y 3. 2/ 2.15Y 3. 2/ 2.15Y 2.9/ 2.0

5Y 3. 2/ 1.65Y 2.9/ 1.45Y 3.0/ 1.35Y 3.0/ 1.35Y 3.0/ 1. 2

5Y 3. 2/ 1.05Y 2.9/ 0. 65Y 2. 9/ 0.65Y 3.0/ 0. 2

5PB 3.0/ 0.2

Normal

4.0RP 4.3/ 4.45. OP 4.1/ 2. 2

5. OPB 4.2/ 2.54. 5RP 4.3/ 6.40. 5RP 4.3/ 4. 5

4. 5RP 4. 2/ 7.94. 5RP 4. 2/ 9. 4

5. OP 4.1/ 4. 25.0RP 4.3/10.70. 5RP 4. 3/ 6. 6

10. OPB 4.1/ 4.65. OP 4.1/ 6.1

0. 5RP 4.3/ 8. 510. OPB 4. 2/ 6.6

5. OP 4.1/ 8. 2

0. 5RP 4. 2/10.410. OPB 4.1/ 8. 5

5. OP 4.1/10.110. OPB 4.0/ 9. 7

5. 5P 4.1/12.6

10.0GY 3. 2/ 4. 54. OG 3. 3/ 4. 8

0. 5GY 3. 3/ 1. 85. OR 4. 2/12. 64. 5R 4. 2/10.8

4. 5R 4. 2/ 9. 44. 5R 4.1/ 6. 8

10. OG 3, 2/ 4. 75.0BG 3.2/ 2.85.0BG 3.1/ 4.1

9. 5RP 4.1/ 6. 46.0BG 3.2/ 5.39. ORP 4. 2/ 8. 29. 5RP 4. 2/ 9. 59.5BG 3.3/ 4.3

5. 5B 3.1/ 2.39. 5BG 3.2/ 5.8

4. 5B 3.1/ 4. 29. 5B 3.1/ 3. 95. OB 3.3/ 5.9

9. 5B 3. 2/ 5. 65. OPB 3.2/ 5.6

9. OB 3. 3/ 7.14.5PB 3.2/ 7.04.5PB 3.4/ 8.54. OPB 3.3/ 9.4

5.0YR 3.3/ 4.110.0YR 3.1/ 2.7

5. OG Y 3. 2/ 2. 65. 5R 4. 2/13. 25. 5R 4. 2/13. 2

10. OR 3. 3/ 5. 4

4.5GY 3.2/ 1.910. OR 3. 2/ 4.1

5.0YR 3.1/ 2.15.0YR 3.1/ 2.0

6. OY 3.1/ 1.1

5. OG 3.1/ 2. 75. OR 3. 2/ 4.64. 5R 3. 4/ 6. 23. 5R 3.1/ 2.12. 5P 3.0/ 0. 2

Color-Blindness 263

TABLE 5. Protanopic arrangement—Continued

Munsellbook

notation

10RP 3/ 4RP 3/ 2

10RP 3/ 6RP 3/ 4

P 3/ 2

PB 3/ 2RP 3/ 810P 3/ 4RP 3/10PB 3/ 4

P3/ 410P 3/ 6

10PB 3/ 4P3 /6

10PB 3/ 6

10P 3/ 8P3 /8

10PB 3/ 8P3/10

10PB 3/10

GY2/ 210Y 2/ 2

Y2/210GY 2/ 210YR 2/ 2

R3/10YR 2/ 2

R3/8G2/2

10R 2/ 2

10G 2/ 25BG 2/ 2BG2/ 4

10BG 2/ 2B2/2

10RP 3/ 8RP3/ 6

10RP3/1010B 2/ 2PB2/ 4

10PB 2/ 4PB2/ 610P 3/10

R2/4R2/2R2/6N 2 /

RP2/ 2

10RP 2/ 410RP 2/ 6

RP2/ 4PB2/ 2

P 2/ 2

RP2/6P2/4

10P 2/ 410PB 2/ 6

10P 2/ 6

P2 /6


0.0569.0611.0562.0590.0722

.0719

.0551

.0665

.0553

.0757

.0679

.0645

.0728

.0711

.0730

.0589

. 0712

.0749

.0700

.0735

.0465

.0475

.0455

.0456

.0472

.0487

.0403

.0519

.0398

.0397

.0445

.0412

.0446

.0507

.0414

.0516

.0549

.0508

.0435

.0437

.0391

.0474

.0531

.0311

.0357

.0359

.0300

.0352

.0336

.0323

.0345

.0378

.0340

.0359

.0344

.0333

.0368

. 0327

.0323

Protanopicchroma-

ticity coor-dinate, Wp

0.4412.4304.4300.4037.3889

.3875

.3540

.3543

.3353

.3415

.3256

.3141

.3128

.•2914

.2858

. 2794

.2611

. 2643

.2224

.2098

.5684

.5609

.5553

.5552

.5419

.5371

.5274

.5241

.5081

.5056

.4967

.4623

.4544

.4400

.4216

.4167

.3837

.3807

. 3664

.3030

.2884

.2802

.2438

.4713

.4663

.4595

.4570

.4204

.4127

.3790

.3691

.3603

.3493

.3385

.3072

.3051

.2767

. 2723

.2580

Munsell renotations

Protanopic

5PB 2.8/ 0.55PB 2.9/ 0.85PB 2.8/ 0.85PB 2.8/ 1.45PB 3.1/ 2.1

5PB 3.1/ 2.15PB 2.7/3.05PB 3.0/ 3. 25PB 2.8/3.75PB 3.2/ 3.9

5PB 3.1/ 4.25PB 3.0/ 4.95PB 3.2/ 5.35PB 3.1/ 6. 25PB 3.2/ 6. 7

5PB 2.8/6.55PB 3.1/ 8.15PB 3.2/ 8. 25PB 3.1/11.05PB3.2/11.8

5Y2.5/ 1.6. 5Y 2. 5/ 1. 5

5Y 2. 5/ 1.45Y 2. 5/ 1.45Y 2. 5/ 1. 2

5Y 2.6/ 1.15Y 2.3/ 0.95Y 2. 7/ 0.9 .5Y 2.3/ 0.65Y 2.3/ 0.6

5Y 2.5/0.45PB 2.3/ 0.15PB 2. 5/ 0.25PB 2.6/ 0. 55PB 2.4/ 0.9

5PB2.7/ 1.05PB2.7/ 2.05PB2.6/ 2.05PB 2.4/ 2.45PB 2.4/ 4. 7

5PB 2.3/ 5.15PB 2. 5/ 5.85PB 2. 7/ 8.3

5Y 2.0/ 0.15 Y 2.2/0.05

5PB 2.0/ 0.15PB 2.0/ 0.15PB 2.1/ 0.9

5PB 2.1/ 1.15PB 2.0/ 1.95PB 2.1/ 2. 25PB 2. 2/ 2. 55PB 2.1/ 2.8

5PB 2. 2/ 3.15PB 2.1/ 4.25PB 2.1/ 4.35PB 2.2/ 5.65PB 2.1/ 5.6

5PB2.0/ 6.2

Normal

9.0RP 3.0/ 3.44.5RP 3.0/ 1.99.0RP 3.1/ 5.65.0RP 3.0/ 3. 7

5. OP 3. 2/ 2. 2

5.0PB 3.1/ 2.15.0RP 3.1/ 6. 810. OP 3. 2/ 4. 5

5.0RP 3. 2/ 8. 45.0PB 3.1/ 3.9

5. OP 3.1/ 4. 59. OP 3. 2/ 6.3

10.0PB3.1/ 4.74. 5P 3.2/ 6.4

10.0PB 3.1/ 6.1

10. OP 3.1/ 8.35. OP 3.2/ 8.4

10.0PB 3. 2/ 7.45. OP 3. 3/11. 2

10. OPB 3.1/10.6

5. 5GY 2. 5/ 2.210. OY 2.6/ 1.65. OY 2. 5/ 1.4

9.5GY2.4/ 2.57.5YR 2.6/ 1.6

5. OR 3.2/ 8.34. 5YR 2.4/ 1.8

5. OR 3.2/ 7. 47. OG 2. 2/ 2.48. 5R 2. 5/ 2.6

10. OG 2.3/ 3.14. 5BG 2. 2/ 2. 55. OB G 2.3/ 3.7.7.0BG2.5/ 3.1

2. OB 2. 2/ 2. 2

9.0RP 3.1/ 7.05.0RP 3.0/ 5. 28. 5RP 3.2/ 8. 5

8. 5B 2. 2/ 3.14. OPB 2.3/ 4.8

10. OPB 2.2/ 4.84. OPB 2.3/ 5.9

9. OP 3.0/ 9.8

4. OR 2.3/ 3.83. 5R 2.3/ 2. 23. OR 2. 5/ 4.85. OP 2.0/ 0. 2

6.0RP 2.3/ 2.3

8. ORP 2.3/ 3. 78. ORP 2.4/ 5.65. ORP 2.4/ 4.64. 5PB 2. 2/ 2. 6

5. 5P 2.1/ 2.9

4. ORP 2.4/ 5.95. OP 2. 2/ 4.69. OP 2. 2/ 5.3

10. OPB 2. 2/ 5. 59. OP 2. 2/ 6.8

5. OP 2.1/ 6. 8

Thus far no precise indication has been given ofthe color perceptions of deuteranopes and pro-tanopes corresponding to the 400 samples in theMunsell Book of Color; we have only groupedtogether those samples that differ least and thatare therefore most likely to be confused. Weknow, however, that deuteranopes and protanopesin all probability perceive black,'gray, and whitenormally; furthermore, we know (see table 3)that their yellow corresponds closely to what thenormal observer sees in the spectrum at 575m/*,and their blue corresponds closely to 470m/i.These facts may be conveniently expressed in theMunsell color system by giving for each set ofvalues of W/Wo and w the Munsell equivalent ofthe purple-blue (PB) or yellow (Y) hue; seemaster hue chart, figure 13 of the OSA Subcom-mittee on the Spacing of the Munsell Colors [76].These Munsell hues correspond closely to those ofthe spectrum at 470 and 575m/x, respectively, andsince the exact hues corresponding to these por-tions of the spectrum depend somewhat on theobserving conditions [14, 17, 96] more precise fit-ting (as by 6PB and 7Y) is probably not warranted.

The deuteranopic and protanopic Munsell re-notations based in this way resulted from thefollowing steps: (a) from table 1 of the OSA Sub-committee Report [76] (pp. 399 and 402) wereread the chromaticity coordinates (x, y) forenough colors of the hues 5Y and 5PB to coverthe range of the Munsell papers; (b) from thesechromaticity coordinates were computed the di-chromatic coordinates wd and wp, according toeq 2d and 2p and these coordinates were tabulatedin table 6; (c) from the data of table 6 families ofcurves were plotted on each of two graphs, onewith wd as the abscissa, the other with wv as theabscissa, the ordinate being Munsell chroma andeach curve showed the variation of Munsellchroma for hue 5Y or 5PB with dichromatic co-ordinate (wd or Wp) for some one Munsell value;(d) from the reflectance relative to magnesiumoxide, W/Wo, (second col of tables 4 and 5), theMunsell value was read from table 2 of the sub-committee report [76]; and (e) by interpolationamong the curves of the corresponding familyaccording to this Munsell value, the Munsell hue(whether 5Y or 5PB) was determined, and theMunsell chroma corresponding to the dichromaticcoordinate, wd or wp, was read with an uncertaintyof about 0.1 chroma step. The Munsell di-


chromatic renotations (Hue Value/Chroma) sofound are given in the fourth column of tables4 and 5. The fifth column is the normal Munsellrenotation copied from table 3 of the subcom-mittee report [76].

Comparison of these two columns (dichromaticMunsell renotation with normal Munsell renota-tion) indicates in a precise and detailed way thedifference between the surface-color perceptionsof the normal observer and those of the averagedeuteranope and average protanope, respectively.

TABLE 6. Deuteranopic and protanopic chromaticity coor-dinates for Munsell renotations of hues

Munsell

renotation

5Y 9/125Y 9/105Y 9/86Y 9/ 65Y 9/ 45Y 9/ 2

5Y 8/125Y 8/106Y 8/ 85Y 8/ 6

5Y 8/45Y 8/ 2

5Y 7/125Y 7/105Y 7/ 85Y 7/6

5Y 7/ 45Y 7/ 2

5Y 6/125Y 6/105Y 6/85Y 6/ 6

5Y 6/ 45Y 6/2

5Y 5/125Y 5/105Y 5/ 85Y 5/ 6

5Y 5/45Y 5/ 2

5Y 4/85Y 4/ 65Y 4/ 4

5Y 4/2

5Y 3/ 65Y 3/45Y 3/ 2

5Y 2/ 45Y 2/ 2

5Y 1/ 2

N 1/ to 9/5PB 9/ 2

Chromaticitycoordinates

Wd

0.8510.7911.7296.6628.5955.5291

.8806

. 8181

.7494

.6764

.6025

.5325

.9125

.8552

.7788

.7007

.6184

.5379

.9425

.8935

.8231

.7346

.6373

.5471

.9903

.9336

.8655

.7783

.6667

.5569

.9153

.8200

.7061

. 5774

.8839

.7373

.5899

.8380

.6149

.7392

.4585

.4362

wp

0. 8433.7827.7218.6569.5929.5305

.8731

.8093

.7408

.6696

.5^93

.5335

.9061

.8466

.7693

.6927

.6139

.5383

.9377

.8859

.8134

.7251

.6314

.5468

.9894

.9279

.8562

. 7677

.6588

. 5556

.9081

.8092

.6962

.5741

.8745

.7261

.5854

. .8266.6182

.7267

.4652

. 4457

Munsell

renotation

5PB 8/ 65PB 8/ 45PB 8/ 2

5PB 7/105PB 7/ 8

5PB 7/ 65PB 7/ 45PB 7/ 2

5PB 6/125PB 6/105PB 6/ 85PB 6/ 65PB 6/ 45PB 6/ 2

5PB 5/125PB 5/105PB 5/ 85PB 5/ 65PB 5/ 45PB 5/ 2

5PB 4/125PB 4/105PB 4/ 85PB 4/ 65PB 4/ 45PB 4/ 2

5PB 3/125PB 3/105PB 3/ 85PB 3/ 65PB 3/ 45PB 3/ 2

5PB 2/125PB 2/105PB 2/ 85PB 2/ 65PB 2/ 45PB 2/ 2

5PB 1/105PB 1/ 8

5PB 1/ 65PB 1/ 45PB 1/ 2

5Y anaI 5PB

Chromaticitycoordinates

ivd

0.3615.3973.4325

.2927

.3246

. 3570

.3913

.4272

.2507

.2804

.3096

.3426

.3823

.4208

.2299

.2577

.2891

.3242

.3662

.4106

.2017

.2282

.2596

.2997

.3442

.3956

.1606

.1886

.2223

.2605

.3104

.3729

.1213

. 1459

.1793

.2247

.2833

.3564

.0998

.1314

.1739

.2337

.3127

wp

0. 3810.4119.4425

.3214

.3489

.3768

.4065

.4377

.2856

.3107

.3354

.3638

.3984

.4319

.2675

.2909

.3176

.3476

.3838

.4226

.2426

.2653

.2919

.3261

.3642

.4091

.2065

.2305

.2594

.2919

.3346

.3890

.1709

.1925

.2215

.2604

.3107

.3740

.1506

.1785

. 2157

. 2671

.3355

It will be noted, of course, first that the normalobserver perceives a multiplicity of hues (red,yellow-red, yellow, green-yellow, green, and so on),while the deuteranope and protanope perceive buttwo—Munsell yellow and Munsell purple-blue.Second, it will be noted from table 4 that the Mun-sell value of each sample for the deuteranope is thesame as that for the normal observer, but fromtable 5 the protanopic and normal Munsell valuediffers except for hues near to yellow-green (3GY)and bluish purple (2P). The reddish colors havelower protanopic values, and the greenish havehigher; the amount of the difference from thenormal values varying from one value step forR 4/14 to zero for nearly neutral colors.

Table 5 also serves to indicate the degree towhich protanopic vision leads to confusions be-tween colors easily distinguishable by a normalobserver. For samples of small size, such as thosethat yield ideal protanopic vision, a difference of0.1-value step or 0.2-chroma step is so small as tobe easily confusible with zero difference. Fromtable 5 it may be seen therefore, that Munsellsamples GY 8/6 and 10Y 8/6 would be confusible toa typical dichromat if viewed in small size, thoughto the normal observer, of course, these twosamples are distinctly different. By proceedingalong the fourth column of table 5 and noting thesamples whose protanopic renotations differ by0.1 or less in value and at the same time by 0.2or less m chroma, we may make an estimate of thefrequency with which a protanope will be troubledto distinguish colors that to the normal observerare separated by at least 10 just noticeable steps.It is found that there are 97 such pairs among the410 different colors listed; that is, in a group ofcolors chosen in such a way as to be unrelated tothe characteristic protanopic confusions, stillabout one-fourth of the colors are by chance con-fusible with another of the group.3 This resultmay explain, on the one hand, why dichromaticobservers often reach maturity without havingbecome convinced that there is anything abnormala,bout them other than unusual unfamiliarity withthe meaning of color terms, since in about three-fourths of the pairs that they are called upon to

s A similar count of pairs confusible by the deuteranope can be made fromthe fourth column of table 4, and about 200 will be found, roughly twice asmany, as from table 5. This is ascribable to the fact that the samples arenot unrelated to deuteranopic confusions, being divisible into seven groups,each composed of samples differing but slightly in deuteranopic Munsellvalue.

Color-Blindness 265

compare, they see a difference but describe it interms not used by the normal obseiver. On theother hand, since one-fourth of the differences thatthe normal observer sees plainly are so slight to thered-green confusing dichromat that he must looklong and closely to decide about them, and oc-casionally fails completely, it is easy to understandthat a characteristic by which the dichromat ismarked is his tendency to hesitate before making adecision, to wait for someone else to speak up,and then to agree with him.

It is suggested that persons who have been foundto have either protanopic or deuteranopic visionby the usual tests might find it interesting andpossibly instructive to lay out the Munsell papersin the order given in table 4 or table 5, as thecase may be, and see to what degree the Munselldichromatic notation accords with their ownperceptions. To the extent that the accord isgood, the person will discover how well his type ofvision is known; and he may be encouraged tostudy the basis of the Munsell dichromatic nota-tion, and so gain an additional insight into therelation of his own vision to that possessed by themajority. If the Munsell dichromatic notationfails to accord with his perceptions in ways not tobe corrected by viewing the papers through bluishor brownish goggles, it is likely that the observerwill find that he has been mistyped by carelessadministration or interpretation of a routine test,and a retest would be in order. Should theobserver find that he is indeed a red-green confus-ing dichromat, he Would have a chance to contrib-ute to the knowledge of color perceptions bystudying and reporting the nature and degree ofany contradictions.

V. Analysis of Color-Blindness Tests inTerms of Dichromatic Munsell Notations

To show how tables 4 and 5 make available thecolor perceptions of deuteranopes and protanopes,respectively, it will be sufficient to analyse a fewof the color-blindness tests based upon light-reflecting objects whose colors are fairly wellestablished.

1. Holmgren Wool Test

Probably the oldest color-blindness test still infairly common use is the famous wool test devel-oped by Holmgren [38]. In this test a considerable

number (50 to 200) of small skeins of differentlycolored yarns are placed in a pile on a flat surfacesufficiently spacious and illuminated with fulldaylight. The skein having the trial color istaken from the pile by the examiner and placedto the side far enough from the others not to beconfused with them during the test. The examinerrequests the subject to pick out the other skeinsthat come closest to the test skein in color and toplace them beside it. Three tests are recommendedby Holmgren, one with a green trial skein, onewith a purple or rose colored skein, and a thirdwith a red skein. The color chart (p. 120) "servesto guide the examiner in the choice of colors forthe test skeins and in appreciating the mistakes ofthe deficients. We have tried to render there thecolors mentioned in this chapter. We dividethem into two classes:

" 1 . The test colors, that is to say, those whichthe examiner offers to the subject, and

"2. The confusion colors, that is to say, thosewhich the deficient picks from the pile because heconfuses them with that of the specimen."

Table 7 gives the Munsell book notations foundin April 1942 for the colors of the chart that formsthe frontispiece of a book [381 s e n t by Holmgrenpersonally to the Smithsonian Institution fromwhich it was turned over on October 10, 1884, tothe Library of Congress as volume 150530. Someof the colors were found to be obviously faded; forexample color I, supposed to be a green (neitheryellow green nor blue green), was found to be aweak greenish yellow, and color Ha, supposed to bea purple, was found to be a light brown. However,the colors relating to the third test seem not tohave faded seriously and will serve as an exampleof how to analyse a color-blindness test by meansof dichromatic Munsell notations.

Of the third test Holmgren says, "The redskein is presented to the subject. It should havea vivid red color like the red flag serving as asignal for the railroads. This color corresponds tol ib of the chart, which ought perhaps to incline alittle more definitely toward yellowish red. Thetest, which is to be made only with subjects thatare completely defective, ought to be continueduntil the subject has placed with the test skeinall of the skeins having that hue, or until he hasselected one or more of the confusion colors (10to 13). The red-blind (protanope, by present-dayterminology) chooses in addition to red some


shades of green and brown (10 and 11) that forthe normal sense appear darker than the red.But the green-blind (deuteranope) chooses con-trasting hues which appear lighter than the red."

The analysis of this test consists in finding thedichromatic Munsell notations of the confusioncolors (10 to 13) and comparing them to thedichromatic Munsell notation of the trial color(lib). From tables 4 and 5, the dichromaticMunsell notations of these five colors have beenobtained by reading the notations for neighboringcolors and interpolating among them. For exam-ple, color l ib was found to have a Munsell booknotation of 5.5R 4.8/10. The two closest colors intable 5 are R 5/10 and 10R 5/10, from which weread protanopic equivalents of Y 4.4/1.5 andY 4.4/4.1, from which in turn by interpolation wewould get a protanopic equivalent of Y 4.4/1.8for 5.5R 5.0/10, and Y 4.2/1.8 for the requiredbook notation 5.5R 4.8/10. This equivalent isgiven in table 7, together with deuteranopic andprotanopic equivalents similarly found for colorslib, 10, 11, 12, and 13.

TABLE 7. Munsell book notations of the color chart publishedby Holmgren to indicate how to administer and interprethis wool test; also dichromatic Munsell renotations of fiveof the colors

Holmgren's—

Description

Green..

Colors confused with green.

PurpleProtanopic confusions with

purple.

Deuteranopic confusionswith purple.

RedProtanopic confusions with

red.

Deuteranopic confusionswith red.

Num-ber

lib1011

1213

Munsell booknotation

9Y 7/46Y6 /21Y 6 12. 54Y8 /5

7YR8 /57YR7 /36YR 6. 5/35PB 3. 0/8

5P 4. 0/6. 5

5Y 5. 5/17G 4. 8/3

5. 5R 4. 8/10j 7GY3.5/2

10YR 3. 6/2

5GY 6. 0/6\ 5YR4.0/6

Dichromatic Munsellrenotation

Protanopic

Y 4. 2/1. 8Y 3.8/1. 5Y 3. 6/2.1

Y 6. 2/6. 2Y 4.0/3. 6

Deuter-anopic

Y 4. 9/3. 5Y 3. 7/1.3Y 3. 7/2. 3

Y 6. 2/5.9Y 4. 4/4. 2

It is evident from an examination of table 7why the pro tan ope would be expected to confusecolors 10 and 11 with the red color l ib. Theprotanopic renotations of these colors differ from

that of the red by 0.6 of a value step or less andby only 0.3-chroma step. Similarly, color 13would be expected to be moderately coniusible bydeuteranopes with the red color l ib, because thedeuteranopic Munsell renotations of these twocolors differ by only 0.5 of a value step and 0.7-chroma step; but color 12 should be distinct fromthe red color l ib to deuteranopes because it islighter by 1.3 value steps and higher in chroma by2.4 steps (compare Y 6.2/5.9 with Y 4.9/3.5).This analysis shows that the colors in Holmgren'sbook conform to his statements regarding the testwith the red skein except for color 12, which wasprobably not correctly rendered origirally by thelithographer. The other discrepancies are toosmall to be significant in view of Holmgren'sstatement: "The resemblance need not be perfectin all respects; there are no two skeins that areexactly alike. The question is particularly onresemblance in hue, and on this account the subjectought to look for those that are similar and belongto the same hue, that which is paler or deeper butof the same color, and so on. . . . Not too muchattention should be paid to lightness nor to slightshades of off-gray color."

Similar analyses of tests by means of green andpurple skeins give similar corroboration of Holm-gren's interpretation of his tests, but these analyseshave to be carried out with reference to the actualcolors of the green and purple skeins used insteadof the faded colors I and Ha of the color chart.

2. Stilling Pseudo-Isochromatic Plates

The plates developed by Stilling in 1878 [91]are still used [71, 93], and copies and develop-ments of them are widely distributed in thiscountry [1, 41]. The subject is shown a series ofprinted pages in succession, each page coveredwith a pattern of irregularly shaped spots. Thespots am so colored and so arranged that numberscan be read on the plates by many observers ofnormal vision, but to observers having varioustypes of abnormal vision certain of the platesseem to have uniform colors or a uniform mixtureof colors, so that no number can be read. Becauseof this, they are called pseudo-isochromatic plates.

The analysis of a psuedo-isochromatic platedesigned to detect protanopia or deuteranopiacan be carried out by obtaining the Munsell booknotations of'typical background spots and typicalspots making up the number, reading their pro-

Color-Blindness 267

tanopic and deuteranopic Munsell notations byinterpolation in tables 4 and 5, and comparingthem. These charts were designed, however, toaccord with a view of the color perceptions ofdichromatic observers developed by Stilling anddescribed by him in detail by means of a color chartprinted in 1909 [92]. It will suffice for illustrationof the method to confine our analysis to theseprinting-ink reproductions of the colors.

Table 8 gives the Munsell book notations ofmost of the colors found in 1944 on the color chartin the Library of Congress copy of Stilling'spaper, tTber Entsteheng und Wesen der Anomaliendes Farbensinnes [92]. The colors dealing withStilling's view of the color perceptions of tritanopeshave been omitted. Table 8 also shows the pro-tanopic and deuteranopic Munsell renotationscorresponding to these book notations read byinterpolation from tables 4 and 5.

From the Munsell book notations of the brown,light brown, and gray colors representing Stilling'sview of what the red-green confuser's color percep-tions are, it may be seen that his idea of the hueof these perceptions is close to that taken in thepresent paper; in no case does his estimate departfrom the present one (5Y) by as much as fiveMunsell hue steps. The value and chroma esti-mates are also fairly close, particularly those forthe color-blind equivalent of blue green;compareY 6.9/4.3 with Y 5.8/3.6 and Y 6.7/3.6 with Y6.0/3.8. The light brown chosen is only slightlydarker (0.9 of a value step) than that which wouldrepresent an average confusion color for protanopeand deuteranope. The yellowish gray shown asan estimate of the color-blind perception of violetis very close to the present estimate of the deuter-anopic perception of the violet shown (compareY 5.7/0.6 with Y 6.2/0.9); but since the namegiven to this sample was gray, the agreement maysignify only that there has been a yellowing of theprinting-ink representation of gray since its pre-paration in 1909. Actually the average of theprotanopic (PB 5.4/0.4) and deuteranopic (Y5.7/0.6) Munsell renotations for the violet shownon the chart is very close to a neutral gray.

The protanopic and deuteranopic confusioncolors for red (7R 4.5/8), also shown in table 8 arenot in very striking agreement; in each case thegreen is too light and of too high a chroma to beconfused by an average protanope or deuteranope.Since the difference between the two colors cor-

responds well with the difference between thepresent estimate of the protanope and deuteranopecolor perceptions, it is reasonable to suppose thatthe greenish printing-ink specimens, like the gray,have yellowed with age by one chroma step since1909. Note that the protanopic equivalent ofthe red is lower in chroma by 3.4 —2.0= 1.4 chromasteps than the deuteranopic equivalent. Thegreen chosen by Stilling as a protanope confusionfor red also gives a dichromatic equivalent oflower chroma (6.0—3.5 = 2.5, 5.8—3.2=2.6) thanthat chosen as the deuteranope confusion for thesame red. The two printing-ink specimens thusgive the correct idea of the difference between thegreens that are confused with red by red-greenconfusers, but the amount of chroma differenceis exaggerated. Similarly, the correct idea of thelightness difference is given (4.6—4.0=0.6), butthe amount is in this case too small (5.6 — 5.4 = 0.2,5.7 — 5.4 = 0.3). Stilling was perfectly well awareof the direction of this difference, because herefers to the protanope confusion green as a "some-what darker green"; whether he had very precisequantitative information cannot be told from thisillustrative example because of the uncertainties

TABLE 8. Munsell book notations of the color chart pub-lished by Stilling [92] to indicate his view of the color per-ceptions and confusions of red-green confusers; also pro-tanopic and deuteranopic Munsell renotations of them

Stilling's description

RedBrown seen by color-blind in-

stead.

PinkLight brown seen instead

VioletGray seen by color-blind in-

stead.

Blue-greenLight brown seen instead

Yellow-greenBrown seen by color-blind in-

stead.

Red. .Yellow-green confused with red

by deuteranope.Green confused with red by

protanope.

Munsell booknotation

7.4R 4.8/90.2Y 5.9/6

7.4R 6.2/82.5Y 5.9/4

9RP 5.5/67.5Y 6.0/1

2G 6.6/82.5Y 5.9/4

8GY 7.3/4.60.2Y 5.9/6

7R 4.5/83GY 5.5/6.0

6GY 5.3/4

Dichromatic Munsellrenotations

Protanopic

Y 4.2/2.6Y 5.9/5.4

Y 5.9/2.1Y 5.8/3.6

PB 5.4/0.4Y 6.2/0.9

Y 6.9/4,3Y 5.8/3.6

Y 7.5/3.7Y 5.9/5.4

Y 4.0/2.0Y 5.6/6.0

Y 5.4/3.5

Deuteran-opic

Y 4.9/4.1Y 6.2/5.8

Y 6.4/3.1Y 6.0/3.8

Y 5.7/0.6Y 6.2/0.9

Y 6.7/3.6Y 6.0/3.8

Y 7.4/3.2Y 6.2/5.8

Y 4.6/3.4Y 5.7/5.8

Y 5.4/3.2


introduced by possible failure of the lithographicprocess to render the colors correctly, and becauseof possible changes of the colors with time.

3. Farnsworth Dichotomous Test (B-20)

The serial order test devised by Farnsworth [20]at the beginning of the war for screening observersinto two groups is particularly easy to analyse interms of dichromatic Munsell notations, becauseit is based upon Munsell papers whose color char-acteristics are known through spectrophotome-try [23, 53]. Table 9 shows the protanopic renota-tions of these papers arranged in the order givenby Farnsworth for a typical protanope; and it alsoshows the deuteranopic renotations of the papersarranged in the order given by Farnsworth for atypical deuteranope. The values of Wp, wp, Wd,and wd are taken from a previous publication [51].

It will be noted that the arrangement of thesepapers made by the observer chosen by Farns-worth as a typical protanope is closely, but notperfectly, given by the protanopic Munsell reno-tation ranging from a yellow of chroma 2.2 througha near neutral (Y 5.2/0.1) to a purple blue ofchroma 3.3. A similar correspondence may alsobe noted between the Farnsworth deuteranopicarrangement and deuteranopic Munsell renota-tion. Possible causes for the failure of the cor-

relation to be perfect are the same as thosepreviously discussed with reference to the chro-maticity coordinates, wv and wd [51]. The chiefcause of the discrepancies seems to be a slight butconsistent difference between the hypotheticalaverage observers defined by eq 1, on the onehand, and the actual observers chosen by Farns-worth as typical on the other. The discrepanciesmay thus be taken as indicating about the degreeof agreement to be expected between an averagered-green confuser and some one observer of thesame type chosen at random.

VI. Summary

A review of the literature on color perceptionsmediated by dichromatic, red-green-confusing,visual mechanisms for an observer capable ofrelating them to normal color perceptions hasbeen carried out, and it shows that both types ofsuch mechanisms (protanopia and deuteranopia)yield color perceptions of two hues, and two huesonly, yellow and blue. A review of the chieftheories of vision shows that they also all providefor this kind of color perception. A method ofderiving protanopic and deuteranopic Munsellnotations of colors from their specification in thestandard ICI colorimetric coordinate system has

TABLE 9. Protanopic and deuteranopic Munsell renotations of the chips of the Farnsworth dichotomous test [20] arrangedin the order found by Farnsworth for a typical protanope and a typical deuteranope, respectively

Protanopic arrangement

1..2_.3_.4..5..

6 -7..8..9_.10.

11.12.13.14.15.

16.17.18.19.20.

Normalserial

number

810769

11512134

31514216

171192018

0.9733 Wp

0.2253.2038.2096.2061.2056

.1813

.1972

.2034

.1818

. 2199

. 2162

.2048

.2103

.2030

.2027

.1942

.2321

.2071

.2164

.2140

Wp

0.5628.5405.5442.5307.5406

.5149

.5011

.5042

.4779

.4709

.4432

.4512

.4684

.4242

.4309

.4145

.4201

.4121

.4042

.3998

ProtanopicMunsell

renotation

Y 5.3/2. 2Y 5. 1/1.7Y 5.1/1.8Y 5.1/1.5Y 5.1/1.7

Y 4.8/1.0Y 5.0/0.8Y 5.1/0.9Y 4.8/0. 3Y 5. 2/0.1

PB 5.2/1.0PB 5.1/0.7

Y 5.1/0.1PB 5.1/2.0PB 5.1/1.6

PB 5.0/2.4PB 5.4/2.3PB 5.1/2.5PB 5.2/3.0PB 5.2/3.3

Deuter-anopic

arrange-ment

Normalserial

numberWd

0.2143.2117.2292.2097.1927

.2185

.2017

.1954

.2229

.2138

.2092

.2077

. 1959

.2043

.1917

.2118

.2087

.2035

.2229

0.5463.5412.5604.5376.5234

. 5153

.5185

.4891

.4761

.4835

.4552

.4320

.4501

.4101

.4227

.4037

.3908

.3891

.4013

.4037

DeuteranopicMunsell

renotation

Y 5.2/1.8Y 5. 2/1.7Y 5. 3/2.1Y 5.1/1.6Y 4.9/1.3

Y 5.2/1.2Y 5.0/1.2Y 5.0/0.6Y 5.3/0.4Y 4.9/0. 5

PB 5.2/0.1PB 5.1/1.1PB 5.1/0.3PB 5.0/2.0PB 5.1/1.6

PB 4.9/2. 2PB 5.2/3.0PB 5.1/3.0PB 5.1/2.5PB 5.3/2.5

Color-Blindness 269

been worked out on the basis of this kind of colorperception. It is concluded that these notationsof colors conform to the usual perceptions of themby protanopic and deuteranopic observers in thesense that the chance of any protanope or deuter-anope of average ocular pigmentation havingvalid ground for objecting to them is remote.These protanopic and deuteranopic Munsell nota-tions therefore serve to relate in a complete anddetailed way the color perceptions of red-green-confusing dichromats with those of normal vision.It is expected that this detailed information willassist in the design of color-blindness tests, andwill help color-blind persons to understand therelation of their own visual systems to the normalsystem and so give them a better chance to avoidthe embarrassments and dangers of living in atridimensional color world with a two-dimensionalcolor detector.

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Color-Blindness 271

color perceptions of deuteranopic and protanopic observers

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