POLICE PHOTOGRAPHYPOLICE PHOTOGRAPHY

Mr. Bayani H. SalamancaMr. Bayani H. SalamancaDean, College of CriminologyDean, College of Criminology

Araullo UniversityAraullo UniversityPHINMA Education NetworkPHINMA Education Network

POLICE PHOTOGRAPHYPOLICE PHOTOGRAPHY

is an art or science that deals with is an art or science that deals with the study of the principles of the study of the principles of photography, the preparation of the photography, the preparation of the photographic evidence, and its photographic evidence, and its application to police work. application to police work.

PHOTOGRAPHY IN CRIMINAL PHOTOGRAPHY IN CRIMINAL INVESTIGATIONINVESTIGATION

Photography Photography is an essential tool for the is an essential tool for the law-enforcement investigator. As a tool, it law-enforcement investigator. As a tool, it enables him to record the visible and in enables him to record the visible and in many cases, the invisible evidences of a many cases, the invisible evidences of a crime. Special techniques employing crime. Special techniques employing infrared, ultra-violet, and X-ray radiation infrared, ultra-violet, and X-ray radiation enable him to record evidence, which is enable him to record evidence, which is not visible. The photographic evidence can not visible. The photographic evidence can then be stored indefinitely and retrieved then be stored indefinitely and retrieved when needed. There is no other process, when needed. There is no other process, which can ferret, record, remember and which can ferret, record, remember and recall criminal evidence as well as recall criminal evidence as well as photography.photography.

Photographs Photographs are also a means of are also a means of communication. It is a language communication. It is a language sometimes defined as the “most sometimes defined as the “most universal of all languages”. universal of all languages”. Photography has an advantage as a Photography has an advantage as a language because it does not rely language because it does not rely upon abstract symbols-words. upon abstract symbols-words. Photography thus is more direct and Photography thus is more direct and less subject to misunderstanding. less subject to misunderstanding.

A. FUNCTIONS OF PHOTOGRAPHY IN A. FUNCTIONS OF PHOTOGRAPHY IN INVESTIGATIVE WORKINVESTIGATIVE WORK

IdentificationIdentification– CriminalCriminal– Missing PersonMissing Person– Lost or stolen propertyLost or stolen property– CivilianCivilian

Communication and Microfilm filesCommunication and Microfilm files– Transmission of photos (wire and radio Transmission of photos (wire and radio

photos)photos)– Investigative report filesInvestigative report files

EvidenceEvidence– Recording and preservingRecording and preserving

Crime scenesCrime scenes

Vehicular accidentsVehicular accidents

Homicide or murderHomicide or murder

Robbery casesRobbery cases

Fires or arsonFires or arson

Object of evidenceObject of evidence

Evidential tracesEvidential traces

– Discovering and provingDiscovering and provingBy contrast controlBy contrast control

By magnificationBy magnification

By invisible radiationBy invisible radiation

Action of offenders (Recording)Action of offenders (Recording)– SurveillanceSurveillance– Burglary trapsBurglary traps– ConfessionsConfessions– Re-enactmentRe-enactment

Court ExhibitsCourt Exhibits– Demonstration enlargementDemonstration enlargement– Individual photosIndividual photos– Projection slidesProjection slides– Motion PicturesMotion Pictures

Crime PreventionCrime Prevention– Security clearance Security clearance Public RelationPublic RelationPolice TrainingPolice Training

– Prepared training films (Police tactics, Prepared training films (Police tactics, investigation techniques)investigation techniques)

– Traffic studiesTraffic studies– Documentations (riots and mob control, Documentations (riots and mob control,

disaster, prison disorders)disaster, prison disorders)Reproduction and copyingReproduction and copying

– PhotographsPhotographs– Official recordsOfficial records

B. PHOTOGRAPHY DEFINEDB. PHOTOGRAPHY DEFINED

It is an art or science which deals It is an art or science which deals with the reproduction of images with the reproduction of images through the action of light, upon through the action of light, upon sensitized materials (film or sensitized materials (film or paper) with the aid of a camera paper) with the aid of a camera and accessories and the and accessories and the chemical processes involved chemical processes involved therein.therein.

PRINCIPLES OF PHOTOGRAPHYPRINCIPLES OF PHOTOGRAPHY

Photograph is both the mechanical Photograph is both the mechanical and chemical result of photography. and chemical result of photography. To produce a photograph, light is To produce a photograph, light is needed aside from sensitized needed aside from sensitized materials (film or paper). Light materials (film or paper). Light radiated or reflected by the subject radiated or reflected by the subject must reach the film while all other must reach the film while all other lights are exclude by placing the film lights are exclude by placing the film inside a light tight box (camera). inside a light tight box (camera).

PHOTOGRAPHPHOTOGRAPH

From the Greek word which means:From the Greek word which means:

- photo means light- photo means light

- graph means to draw- graph means to draw

The effect of light on the film is not visible The effect of light on the film is not visible in the formation of images of objects. To in the formation of images of objects. To make it visible, we need or required a make it visible, we need or required a chemical processing of the exposed film chemical processing of the exposed film called development.called development.

The visual effect of light on the film The visual effect of light on the film after development varies with the quantity after development varies with the quantity or quality of light that reached the or quality of light that reached the emulsion of the film. Too great in the emulsion of the film. Too great in the amount of light will produce an opaque or amount of light will produce an opaque or very black shade after development. Too very black shade after development. Too little will produce a transparent or white little will produce a transparent or white shade after development. shade after development.

The amount of light reaching the film The amount of light reaching the film is dependent upon several factors is dependent upon several factors like lightning condition, lens opening like lightning condition, lens opening used, shutter speed used, filter used, used, shutter speed used, filter used, etc..etc..

HOW DOES THE LIGHT HOW DOES THE LIGHT TRAVELS?TRAVELS?

C. DIFFERENT PHOTOGRAPHIC C. DIFFERENT PHOTOGRAPHIC RAYSRAYS

X-ray – radiation having a wavelength X-ray – radiation having a wavelength between .01 to .30 nanometer or milli-between .01 to .30 nanometer or milli-microns. They are produced by passing microns. They are produced by passing an electric current through a special type an electric current through a special type of vacuum tube.of vacuum tube.Ultra-violet rays – radiation having a Ultra-violet rays – radiation having a wavelength from 30 to 400 milli-microns. wavelength from 30 to 400 milli-microns. It is used to photograph fingerprints on It is used to photograph fingerprints on multi-colored background, documents multi-colored background, documents that are altered chemically or over that are altered chemically or over writings and detection of secret writings.writings and detection of secret writings.

Visible light rays or White light – Visible light rays or White light – rays having a wavelength of 400 to rays having a wavelength of 400 to 700 milli-microns. 700 milli-microns. Infra-red rays radiation having a Infra-red rays radiation having a wavelength of 700 to 1000 milli-wavelength of 700 to 1000 milli-microns. It is used in taking microns. It is used in taking photographs of obliterated writing, photographs of obliterated writing, burnt or dirty documents or burnt or dirty documents or blackout photography. blackout photography.

COLORS IN PHOTOGRAPHYCOLORS IN PHOTOGRAPHY

THE PRIMARY COLORSTHE PRIMARY COLORS

THE SECONDARY COLORSTHE SECONDARY COLORS

D. TYPES OF LIGHTNING CONDITIOND. TYPES OF LIGHTNING CONDITION

Natural (Sunlight)Natural (Sunlight)a. Bright- object in open space casts a. Bright- object in open space casts

a deep and uniform shadowa deep and uniform shadowb. Hazy – object in open space casts b. Hazy – object in open space casts

a transparent shadow a transparent shadow c. Dull – object in open space casts c. Dull – object in open space casts

no shadowno shadow

ArtificialArtificial

– Continuous radiation – incandescent Continuous radiation – incandescent lamps, fluorescent lamps, photoflood lamps, fluorescent lamps, photoflood lamps, etc.lamps, etc.

– Short duration – chemical flash (Flash Short duration – chemical flash (Flash bulb), electronic flash.bulb), electronic flash.

E. TYPES OF FILM ACCORDING TO E. TYPES OF FILM ACCORDING TO

SPECTRAL SENSITIVITYSPECTRAL SENSITIVITY

Perhaps the most important Perhaps the most important characteristics of a film is its characteristics of a film is its variation in response to the variation in response to the different wavelength of light source different wavelength of light source which is called spectral sensitivity.which is called spectral sensitivity.

Blue sensitive – sensitive to ultra-violet Blue sensitive – sensitive to ultra-violet rays and blue color only.rays and blue color only.

Orthochromatic – sensitive to ultra-violet Orthochromatic – sensitive to ultra-violet rays, to blue and green color. It is not rays, to blue and green color. It is not sensitive to red color. sensitive to red color.

Panchromatic – sensitive to ultra-violet Panchromatic – sensitive to ultra-violet rays, to blue, green and red color.rays, to blue, green and red color.

Infra-red – sensitive to ultra-violet rays, Infra-red – sensitive to ultra-violet rays, to all the colors, and also infra-red rays.to all the colors, and also infra-red rays.

F. EMULSION SPEEDF. EMULSION SPEED

The extent to which an emulsion is The extent to which an emulsion is sensitive to light is referred to its sensitive to light is referred to its emulsion speed. emulsion speed.

Emulsion ColorsEmulsions are thin, gelatinous, light-sensitive coatings on film that react chemically to capture the color and shadings of a scene. The four layers pictured here show the same image as it would appear on different emulsions in photographic film after the first stage of developing. For black-and-white photographs, only one emulsion is required, because it is the amount of light, not the color, that activates the chemical reaction. Color film requires three layers of emulsions, each of which is sensitive to only one of the primary colors of light: blue, green, or red. As light passes through the layers, each emulsion records areas where its particular color appears in the scene. When developed, the emulsion releases dye that is the complementary color of the light recorded: blue light activates yellow dye, green light is magenta, and red light is cyan (bluish-green). Complementary colors are used because they produce the original color of the scene when the film is processed.Microsoft ® Encarta ® Reference Library 2004. © 1993-2003 Microsoft Corporation. All rights reserved.

ASA (American Standards Association) ASA (American Standards Association)

-- This is expressed in arithmetical This is expressed in arithmetical value system. The speeds in numbers are value system. The speeds in numbers are directly proportional to the sensitivity of directly proportional to the sensitivity of the material. A film with an arithmetical the material. A film with an arithmetical value of 400 is four times as fast as one value of 400 is four times as fast as one with a speed of 100. with a speed of 100.

The two general types of speed ratings are:The two general types of speed ratings are:

DIN (Deutche Industri Normen) Rating DIN (Deutche Industri Normen) Rating

- This is expressed in logarithmic value - This is expressed in logarithmic value system. In this system an increase of 3 system. In this system an increase of 3 degrees double the sensitivity.degrees double the sensitivity.

ISO Rating (combination of ASA and DIN ISO Rating (combination of ASA and DIN rating)rating)

G. CHARACTERISTICS OF G. CHARACTERISTICS OF PHOTOGRAPHIC PAPERPHOTOGRAPHIC PAPER

According to chemical contents – According to chemical contents – chloride papers, bromide papers, chloride papers, bromide papers, chloro-bromide papers.chloro-bromide papers.According to contrast #0, #1, #2, According to contrast #0, #1, #2, #3#3According to physical According to physical characteristics – weight (single, characteristics – weight (single, double) surface (glossy, semi-double) surface (glossy, semi-matte, matte) color (white, cream).matte, matte) color (white, cream).

H. CAMERAH. CAMERA AA camera camera is basically nothing more than a is basically nothing more than a light tight box with a pinhole or a lens, light tight box with a pinhole or a lens, shutter at one end and a holder of shutter at one end and a holder of sensitized material at the other. While sensitized material at the other. While there are various kinds of camera from the there are various kinds of camera from the simplest construction (Box-type) to the simplest construction (Box-type) to the most complicated, all operate on the same most complicated, all operate on the same principles. The exposure of the sensitized principles. The exposure of the sensitized material to light is controlled by the lens material to light is controlled by the lens and its aperture, and the shutter through and its aperture, and the shutter through its speed in opening and closing of lens to its speed in opening and closing of lens to light.light.

The essential parts of a camera are: The essential parts of a camera are: a light tight box, a lens, a shutter, a a light tight box, a lens, a shutter, a holder of sensitized material, and holder of sensitized material, and viewfinder. All other accouterment of viewfinder. All other accouterment of any camera merely make picture any camera merely make picture taking easier, faster, and convenient taking easier, faster, and convenient for the operator and are called for the operator and are called accessories.accessories.

Body or Light Tight Box Body or Light Tight Box

- suggest an enclosure devoid or light. An - suggest an enclosure devoid or light. An enclosure, which would prevent light from enclosure, which would prevent light from exposing the sensitized material inside the exposing the sensitized material inside the camera. This does not necessarily mean that camera. This does not necessarily mean that the box or enclosure to always light tight at all the box or enclosure to always light tight at all the times because if it does, then no light could the times because if it does, then no light could reach the sensitized material during exposure. reach the sensitized material during exposure. It means that before and after the extraneous It means that before and after the extraneous light, which is not necessary to form the final light, which is not necessary to form the final images.images.

Lens Lens

– – the function of the lens is to the function of the lens is to focus the light coming from the focus the light coming from the subject. It is chiefly responsible for subject. It is chiefly responsible for the sharpness of the image formed the sharpness of the image formed through which light passes during through which light passes during the exposure.the exposure.

Shutter Shutter

– – is used to allow light to enter is used to allow light to enter through the lens and reach the film through the lens and reach the film for a pre-determined interval of time, for a pre-determined interval of time, which light is again blocked off from which light is again blocked off from the film the film

Holder of sensitized material Holder of sensitized material

– – located at the opposite side located at the opposite side of the lens. Its function is to hold of the lens. Its function is to hold firmly the sensitized material in it’s firmly the sensitized material in it’s placed during exposure to prevent placed during exposure to prevent the formation of a multiple or the formation of a multiple or blurred image of the subject.blurred image of the subject.

View-finder View-finder

– – it is a means of determining it is a means of determining the field of view of the camera or the field of view of the camera or the extent of the coverage of the the extent of the coverage of the lens.lens.

I. INHERENT DEFECTS OF LENSESI. INHERENT DEFECTS OF LENSES

Spherical Aberration Spherical Aberration

– – photographic rays passing photographic rays passing through the edges of a lens are through the edges of a lens are bent or refracted more sharply than bent or refracted more sharply than those passing through the central those passing through the central part of the lens, thus they coming part of the lens, thus they coming to a focus nearer the lens than to a focus nearer the lens than those of the central rays.those of the central rays.

Coma Coma

– – sometimes known as lateral spherical sometimes known as lateral spherical aberration. It concern with rays entering aberration. It concern with rays entering the lens obliquely. the lens obliquely.

Curvature of the filed Curvature of the filed

– – when the image formed by a lens when the image formed by a lens comes to a sharper focus on curved comes to a sharper focus on curved surface than on a flat surface.surface than on a flat surface.

Distortion – outer parts of the image Distortion – outer parts of the image produced by the lens will be produced by the lens will be magnified either less or more than magnified either less or more than the center image.the center image.

– Barrel distortion – diaphragm is placed Barrel distortion – diaphragm is placed in front of the lens.in front of the lens.

– Pincushion distortion – diaphragm is Pincushion distortion – diaphragm is placed behind the lens.placed behind the lens.

Chromatic Aberration Chromatic Aberration

– – inability of the lens to focus all the inability of the lens to focus all the colors in the same place.colors in the same place.

Astigmatism Astigmatism

– – inability of the lens to focus lines inability of the lens to focus lines running in different direction like for running in different direction like for example a cross.example a cross.

Chromatic difference by magnification Chromatic difference by magnification

– – inability of the lens to produce image inability of the lens to produce image sizes of objects with different colors.sizes of objects with different colors.

Flares Flares

a. opticala. optical

b. mechanicalb. mechanical

J. TYPES OF LENSES AS ACCORDING J. TYPES OF LENSES AS ACCORDING TO THEIR DEGREE OF CORRECTIONTO THEIR DEGREE OF CORRECTION

Achromatic lens – a lens corrected Achromatic lens – a lens corrected for chromatic aberration.for chromatic aberration.Rapid Rectilinear – lens corrected Rapid Rectilinear – lens corrected for distortion.for distortion.Anastigmat lens – lens corrected for Anastigmat lens – lens corrected for astigmatism.astigmatism.Apochromat lens – lens corrected Apochromat lens – lens corrected for astigmatism but with a higher for astigmatism but with a higher correction of color.correction of color.

K. LENS CHARACTERISTICSK. LENS CHARACTERISTICS

Focal length – is the distance Focal length – is the distance measured from the optical center of measured from the optical center of the lens to the film plane when the the lens to the film plane when the lens is set of focused at infinity lens is set of focused at infinity position. As according to focal position. As according to focal length, lenses maybe classified as:length, lenses maybe classified as:

– Wide-angle lens – a lens with a focal length of Wide-angle lens – a lens with a focal length of less than the diagonal of its negative less than the diagonal of its negative material. material.

– Normal lens – a lens with a focal length of Normal lens – a lens with a focal length of approximately equal or more but not more approximately equal or more but not more than twice the diagonal of its negative than twice the diagonal of its negative material.material.

– Long or Telephoto lens – a lens with a focal Long or Telephoto lens – a lens with a focal length of more than twice the diagonal of its length of more than twice the diagonal of its negative material. negative material.

Relative aperture – the light gathering Relative aperture – the light gathering power of the lens is expressed in the F-power of the lens is expressed in the F-number system. It is it is otherwise called number system. It is it is otherwise called the relatives aperture.the relatives aperture.

It is an opening that changes in size to It is an opening that changes in size to admit more or less light (similar to the admit more or less light (similar to the iris of an eye). The numbers on the iris of an eye). The numbers on the aperture control are called F-stops and aperture control are called F-stops and referred to as F16, F11, F8, and so on. referred to as F16, F11, F8, and so on.

By increasing or decreasing the F-By increasing or decreasing the F-number (F-stops) numerically, it is number (F-stops) numerically, it is possible to:possible to:

– control has the amount of light passing control has the amount of light passing through the lens through the lens

– control the depth of field control the depth of field – control the degree of sharpness due to control the degree of sharpness due to

the lens defects.the lens defects.

The aperture control may look something like this:The aperture control may look something like this:

Here's how it works: Here's how it works:

– The larger the F-stop number, the The larger the F-stop number, the smaller the opening. smaller the opening.

– Each number higher lets in half as much Each number higher lets in half as much light as one number lower. light as one number lower.

For example, F5.6 admits twice as much For example, F5.6 admits twice as much light as F8, while F11 lets in only half as light as F8, while F11 lets in only half as

much.much.

The aperture doesn't work alone, The aperture doesn't work alone, however. The shutter speed is however. The shutter speed is responsible for exposure, too. It responsible for exposure, too. It controls the amount of time light is controls the amount of time light is allowed to reach the film. allowed to reach the film.

Depth of field – is the distance Depth of field – is the distance measured from the nearest to the measured from the nearest to the farthest object in apparent sharp farthest object in apparent sharp focus when the lens is set or focused focus when the lens is set or focused at a particular distance.at a particular distance.

Hyper focal distance – is the nearest Hyper focal distance – is the nearest distance at which a lens is focused distance at which a lens is focused with a given particular diaphragm with a given particular diaphragm opening which will give the opening which will give the maximum depth of field.maximum depth of field.

Focusing – is the setting of the Focusing – is the setting of the proper distance in order to form a proper distance in order to form a sharp image a lens of a camera sharp image a lens of a camera except those fixed focused requires except those fixed focused requires focusing. A lens maybe focused by focusing. A lens maybe focused by any of the following.any of the following.

- Focusing scale or scale bed – a scale is - Focusing scale or scale bed – a scale is usually found at the lens barrel indicating usually found at the lens barrel indicating pre-settled distance in feet or in meters. pre-settled distance in feet or in meters. To focus the lens of the camera, the To focus the lens of the camera, the distance of the object to be distance of the object to be photographed is measured, estimated, or photographed is measured, estimated, or calculated and the pointer or maker on calculated and the pointer or maker on the lens barrel is adjusted to the the lens barrel is adjusted to the corresponding number on the scale.corresponding number on the scale.

Range-finders – is a mechanism Range-finders – is a mechanism that measures the angle of the that measures the angle of the convergence of light coming from a convergence of light coming from a subject as seen from two apertures. subject as seen from two apertures. There are two types of range-There are two types of range-finders:finders:

- - Split-image through the range finder, the Split-image through the range finder, the image of a straight line in the object appears to image of a straight line in the object appears to be cut into halves and separated from each be cut into halves and separated from each other when the lens is not in focus. When the other when the lens is not in focus. When the images of the lines are aligned, the lens is in images of the lines are aligned, the lens is in focus.focus.

- Co-incident image – through the eyepiece, a - Co-incident image – through the eyepiece, a single image is seen double when the subject single image is seen double when the subject is out of focus. Make the image concede and is out of focus. Make the image concede and the lens is in focus.the lens is in focus.

. Ground Glass – is focused by . Ground Glass – is focused by directly observing the image formed directly observing the image formed at the ground glass, screen placed at the ground glass, screen placed behind the taking lens. If the image behind the taking lens. If the image formed is blurred, fuzzy, or not clear, formed is blurred, fuzzy, or not clear, the lens is out of focus. Make the the lens is out of focus. Make the image sharp, the lens is in focus.image sharp, the lens is in focus.

Zone – this is possible in wide angle Zone – this is possible in wide angle lenses only. There are only three lenses only. There are only three settings for focusing. One for close settings for focusing. One for close distance (approximately 3-6 ft) distance (approximately 3-6 ft) another for the medium distance another for the medium distance (approximately 6-15 ft) and finally for (approximately 6-15 ft) and finally for distance objects (approximately 15 distance objects (approximately 15 infinity).infinity).

L. ShutterL. Shutter

– – A contraption or device used to block A contraption or device used to block the path of light passing through the the path of light passing through the lens and exposing the sensitized lens and exposing the sensitized material. material.

- is a device that opens and closes at - is a device that opens and closes at varying speeds to determine the varying speeds to determine the amount of time the light entering the amount of time the light entering the aperture is allowed to reach the film. aperture is allowed to reach the film.

Shutter speed is measured in fractions of a Shutter speed is measured in fractions of a second. 125 means 1/125 of a second, 60 second. 125 means 1/125 of a second, 60 means 1/60. Typical shutter speeds range means 1/60. Typical shutter speeds range from 1 second to 1/1000. A shutter speed from 1 second to 1/1000. A shutter speed setting for a bright, sunny day - using an setting for a bright, sunny day - using an aperture of F11 - might be 1/125 second. A aperture of F11 - might be 1/125 second. A cloudy day might use 1/60 second with the cloudy day might use 1/60 second with the same aperture, exposing the film to light same aperture, exposing the film to light for a longer period of time. for a longer period of time.

The settings for a good exposure are The settings for a good exposure are determined by a light meter. (Most 35mm determined by a light meter. (Most 35mm cameras have a built-in light meter that cameras have a built-in light meter that shows you the appropriate settings, or shows you the appropriate settings, or automatically controls them.) automatically controls them.)

Aperture and shutter settings work Aperture and shutter settings work together. Because the shutter (like the together. Because the shutter (like the aperture) approximately halves or doubles aperture) approximately halves or doubles the light reaching the film with each the light reaching the film with each change in setting, a number of different change in setting, a number of different combinations of settings can result in the combinations of settings can result in the same exposure. same exposure.

Aperture F22 F16 F11 F8 F5.6

Shutter1/30

1/60

1/125

1/250

1/500

Any of the combinations shown above would result in approximately the same exposure.

- Generally there are two types of shutters:- Generally there are two types of shutters:

Central Shutters – one that is located near Central Shutters – one that is located near the lens (usually between the element of the lens (usually between the element of the lens). It is made of metal leaves and the lens). It is made of metal leaves and its action starts from the center toward the its action starts from the center toward the side then closes back to the center.side then closes back to the center.

Focal Plane Shutter – is located near the Focal Plane Shutter – is located near the focal place or the sensitized material. It is focal place or the sensitized material. It is usually made of cloth curtain. Its action usually made of cloth curtain. Its action starts on one side and closes on the starts on one side and closes on the opposite sides.opposite sides.

M. ExposureM. Exposure

– – is the product of illumination and time. is the product of illumination and time. Exposure is computed by any of the following Exposure is computed by any of the following methods. methods.

1. 1. Use of light or exposure meter. The Use of light or exposure meter. The amount of light coming form a source or amount of light coming form a source or the amount of light being reflected by the amount of light being reflected by the subject is measured by the light the subject is measured by the light meter. Proper adjustment therefore meter. Proper adjustment therefore becomes simplified.becomes simplified.

2.2. By taking into consideration By taking into consideration exposure factors like; exposure factors like; emulsion emulsion speed or film sensitivity, lightning speed or film sensitivity, lightning condition, kind of subject.condition, kind of subject.

Example : Example : When using a film with an ASA When using a film with an ASA rating of 100, for a normal subject, set rating of 100, for a normal subject, set the shutter speed at 1/25 of a second the shutter speed at 1/25 of a second and adjust the diaphragm opening in and adjust the diaphragm opening in accordance with the following lightning accordance with the following lightning conditions. conditions.

Bright sunlight – f-11Bright sunlight – f-11Hazy sunlight – f-8Hazy sunlight – f-8Dull sunlight – f-5.6Dull sunlight – f-5.6

Exposure errors affects: Exposure errors affects: a. detaila. detailb. tone reproductionb. tone reproductionc. contrastc. contrast

Aperture F22 F16 F11 F8 F5.6

Shutter 1/30 1/60 1/125 1/250 1/500

N. CHEMICAL PROCESSINGN. CHEMICAL PROCESSING

Development – is the process of reduction. Development – is the process of reduction. Expose silver halides are reduced into metallic Expose silver halides are reduced into metallic silver. There is a separate developer for film (D-silver. There is a separate developer for film (D-76) and another for paper (Dektol). The factors 76) and another for paper (Dektol). The factors that affect developing time are: agitation, that affect developing time are: agitation, temperature, concentration of chemicals and temperature, concentration of chemicals and exposure.exposure.

Stop-Bath – an intermediate bath between the Stop-Bath – an intermediate bath between the developer and the fixer. It is usually a developer and the fixer. It is usually a combination of water plus acetic acid or just combination of water plus acetic acid or just plain water. Primarily, its function is to prevent plain water. Primarily, its function is to prevent the contamination of two chemical solutions.the contamination of two chemical solutions.

Fixation – the process of removing Fixation – the process of removing unexposed silver halide remaining in the unexposed silver halide remaining in the emulsion after the first stage of the emulsion after the first stage of the development of the latest image. The development of the latest image. The usual composition of an acid fixing usual composition of an acid fixing solution are solvent silver halide known solution are solvent silver halide known as hypo, an anti-staining agent like as hypo, an anti-staining agent like acetic acid, preservative like sodium acetic acid, preservative like sodium sulfite, and a hardening agent like sulfite, and a hardening agent like potassium alum.potassium alum.

Processing Method – negative-positive Processing Method – negative-positive method, reversal methodmethod, reversal method

Developing FilmDeveloping photographic film requires a series of chemical baths that cause the latent image on the exposed film to become visible as a negative. The

process begins with the developer (1), which causes metallic silver to form where the film has been exposed

to light, in densities that depend on the amount of exposure. To stop the action of the developer, film goes into a stop bath (2). After a rinse in water, the film goes into a fixer (3) to removes any silver salts not converted

to metallic silver. After a short rinse, the film is submerged in fixer remover (4) to clear any remaining fixer from the film. The final bath (5) is a thorough rinse in water. The developed negative is then allowed to dry.

Printing PhotographsPrinting PhotographsProducing a photographic print from a developed Producing a photographic print from a developed

negative alsonegative also requires a series of chemical baths. The requires a series of chemical baths. The process begins by projecting light from an enlarger process begins by projecting light from an enlarger

through the negative and onto a piece of photographic through the negative and onto a piece of photographic paper (paper treated with a light-sensitive coating). A paper (paper treated with a light-sensitive coating). A

developer bath (1) makes the positive image visible on developer bath (1) makes the positive image visible on

the paper; a stop bath (2) stops the action ofthe paper; a stop bath (2) stops the action of the the developer so the print won't continue to darken; and a developer so the print won't continue to darken; and a fixer bath (3) and a thorough rinse in water (4) remove fixer bath (3) and a thorough rinse in water (4) remove any remaining reactive chemicals. The finished print any remaining reactive chemicals. The finished print

then dries.then dries.

CHEMICAL COMPOSITION OF CHEMICAL COMPOSITION OF DEVELOPERDEVELOPER

Reducers or developing agents – Reducers or developing agents – Elon, HydroquinoneElon, Hydroquinone

Preservative – sodium sulfite Preservative – sodium sulfite

Accelerator – sodium carbonateAccelerator – sodium carbonate

Restrainer or fog preventer – Restrainer or fog preventer – potassium bromide potassium bromide

CHEMICAL COMPOSITION OF A FIXERCHEMICAL COMPOSITION OF A FIXER

Dissolving agent – Hypo or sodium Dissolving agent – Hypo or sodium thiosulfate thiosulfate

Preservative – sodium sulfitePreservative – sodium sulfite

Neutralizer – boric acid, acetic acid Neutralizer – boric acid, acetic acid

Hardener – potassium alumHardener – potassium alum

FACTORS THAT AFFECTING FACTORS THAT AFFECTING DEVELOPING TIMEDEVELOPING TIME

Characteristic of negative material Characteristic of negative material Strength and composition of the Strength and composition of the developerdeveloperTemperature of the developing Temperature of the developing solutionsolutionAgitation or stirring during Agitation or stirring during developmentdevelopment

O. ENLARGING TECHNIQUESO. ENLARGING TECHNIQUES

After processing an exposed film into a After processing an exposed film into a negative, the next step would be to turn negative, the next step would be to turn the negative into a positive print or copy. the negative into a positive print or copy. This could be done by either contact This could be done by either contact printing or projection printing. For contact printing or projection printing. For contact printing, a contact printer is used while in printing, a contact printer is used while in projection printing an enlarger is needed. projection printing an enlarger is needed.

FOUR ESSENTIAL PARTS OF AN FOUR ESSENTIAL PARTS OF AN ENLARGERENLARGER

1. a base and stand 1. a base and stand

2. a lamp house 2. a lamp house

3. a condenser or diffuser 3. a condenser or diffuser

4. a lens 4. a lens

ACCESSORIES OF THE ACCESSORIES OF THE ENLARGERENLARGER

1. a negative holder 1. a negative holder

2. easel (Paper holder)2. easel (Paper holder)

STEPS IN ENLARGINGSTEPS IN ENLARGINGPreparation of the darkroom, chemicals Preparation of the darkroom, chemicals and the enlarger.and the enlarger.

Put off white light, switch on red light.Put off white light, switch on red light.

Place the negative in the negative holder Place the negative in the negative holder with the dull side of the negative facing with the dull side of the negative facing down.down.

Insert the negative holder into the Insert the negative holder into the enlarger.enlarger.

Switch on the enlarger’s light.Switch on the enlarger’s light.

Adjust the easel to the desired size of the Adjust the easel to the desired size of the photograph.photograph.Focus the lens of the enlarger. Focusing Focus the lens of the enlarger. Focusing is done by first opening the lens is done by first opening the lens diaphragm fully. After the image has diaphragm fully. After the image has been focused, and the density of the been focused, and the density of the negative permits, the lens of the enlarger negative permits, the lens of the enlarger must be stop down a little bit.must be stop down a little bit.Switch off the light of the enlarger.Switch off the light of the enlarger.Insert the photographic paper in the Insert the photographic paper in the easel with the shinny side facing up.easel with the shinny side facing up.Make the exposure.Make the exposure.

Immerse the exposed photographic Immerse the exposed photographic paper in the developer. The usual paper in the developer. The usual developing time for a normally exposed developing time for a normally exposed paper is about 1 to 1½ minutes.paper is about 1 to 1½ minutes.Transfer the developed print in the stop Transfer the developed print in the stop bath for about 30 seconds.bath for about 30 seconds.Place the prints in the acid fixer. The Place the prints in the acid fixer. The fixing time is about 30 minutes.fixing time is about 30 minutes.Wash the prints in running water for Wash the prints in running water for about 20 to 30 minutes.about 20 to 30 minutes.DryingDryingMountingMounting

REMEDYING CHEMICAL REMEDYING CHEMICAL DEFECTS IN NEGATIVESDEFECTS IN NEGATIVES

– Underdeveloped -IntensifierUnderdeveloped -Intensifier– Overdeveloped – reducerOverdeveloped – reducer– Stains – Stain removerStains – Stain remover

FREQUENT FAULTS IN FREQUENT FAULTS IN PRINTINGPRINTING

Blurred exhibitsBlurred exhibitsMuddy and mottled exhibitsMuddy and mottled exhibitsYellowish exhibitsYellowish exhibitsDark exhibitsDark exhibitsLight exhibitsLight exhibitsHarsh exhibitsHarsh exhibitsFlat exhibitsFlat exhibitsFogged exhibitsFogged exhibitsBlemishes on printsBlemishes on printsDistorted printsDistorted prints

P. CRIME SCENE PHOTOGRAPHYP. CRIME SCENE PHOTOGRAPHY

PHOTOGRAPHIC PROCEDURESPHOTOGRAPHIC PROCEDURESThe camera should be mounted on a sturdy The camera should be mounted on a sturdy tripod whenever to prevent camera tripod whenever to prevent camera movement.movement.The camera should be leveled whenever The camera should be leveled whenever commensurate with the particular commensurate with the particular photograph to be taken.photograph to be taken.Crime scene views include three general Crime scene views include three general classes.classes.– Long views, showing general location and Long views, showing general location and

conditions.conditions.– Medium views, pinpointing a specific object of Medium views, pinpointing a specific object of

evidence or significant segment of the crime evidence or significant segment of the crime scene.scene.

– Close-up views, recording position and details.Close-up views, recording position and details.

Photographs should be taken Photographs should be taken progressively as the photographer enters progressively as the photographer enters the building or room to avoid disturbing the building or room to avoid disturbing something that might otherwise remain something that might otherwise remain unnoticed, and to maintain continuity.unnoticed, and to maintain continuity.

Views should be taken to illustrate the Views should be taken to illustrate the general location of the scene of the general location of the scene of the crime. A large outdoors scene or a crime. A large outdoors scene or a matter involving several buildings may matter involving several buildings may call for any material view.call for any material view.

Definitely required is the view of exterior Definitely required is the view of exterior of the building when the crime was of the building when the crime was committed inside. It is well to include the committed inside. It is well to include the street number when this is possible.street number when this is possible.7. Needed next is the complete 7. Needed next is the complete photographic coverage of the inferior photographic coverage of the inferior rooms within a crime area which show the rooms within a crime area which show the condition in general and relate the overall condition in general and relate the overall scene to specific items and places.scene to specific items and places.8. Bodies of victims should be 8. Bodies of victims should be photographed exactly as found from all photographed exactly as found from all angles and especially from overhead when angles and especially from overhead when this can be done for identification this can be done for identification purposes.purposes.

- Close-up photographs, one to one, if - Close-up photographs, one to one, if possible, should be taken all wounds, bruises, possible, should be taken all wounds, bruises, discolorations and abrasions-generally with discolorations and abrasions-generally with colors.colors.

Measuring devices such as rulers, yardstick, and Measuring devices such as rulers, yardstick, and tape measures can be used to show the relative tape measures can be used to show the relative size of and distance between objects or the size of and distance between objects or the degree of magnification of an enlargement. There degree of magnification of an enlargement. There should obscure any important part of the should obscure any important part of the evidence. In photographing a document for evidence. In photographing a document for example, the ruler a six inches (or 15 centimeter) example, the ruler a six inches (or 15 centimeter) is placed at the bottom or just below the object is placed at the bottom or just below the object will show the relative size of objects in a will show the relative size of objects in a photographing exhibit.photographing exhibit.

Field notes.Field notes.-Record the date and time of arrival at the crime -Record the date and time of arrival at the crime

scene as well as the time of departure from the scene.scene as well as the time of departure from the scene.

-Specifically record the location area, street -Specifically record the location area, street number, name of building, type of scene.number, name of building, type of scene.

-Write down the names and badge numbers of all -Write down the names and badge numbers of all investigative officers present during photographing.investigative officers present during photographing.

-Total and record the number of exposures, which -Total and record the number of exposures, which necessitates the bad negatives and be saved for the necessitates the bad negatives and be saved for the record.record.

-Record specific information on each exposure. -Record specific information on each exposure. This should include the time of taking of each pictures, This should include the time of taking of each pictures, which can be expressed either using AM or PM or on which can be expressed either using AM or PM or on military type 24 hour scales which 3:00 PM becomes military type 24 hour scales which 3:00 PM becomes 1500 hours.1500 hours.

Additionally:Additionally:

-Direction of camera where it -Direction of camera where it was pointedwas pointed

-General statement of what -General statement of what has been photographedhas been photographed

-Exposure to ASA rating-Exposure to ASA rating

-Kind of film-Kind of film

-The lighting, whether -The lighting, whether available, flood lamps, flash available, flood lamps, flash lamps, etc. lamps, etc.

Problems in FingerprintProblems in FingerprintPhotographyPhotography

– Black fingerprint on colored backgroundBlack fingerprint on colored background– White fingerprint on colored backgroundWhite fingerprint on colored background– Fingerprint on multi-colored backgroundFingerprint on multi-colored background– Fingerprint on glassFingerprint on glass– Fingerprint on Polished metalFingerprint on Polished metal– Fingerprint on papersFingerprint on papers

PROBLEMS IN QUESTIONED PROBLEMS IN QUESTIONED DOCUMENTS PHOTOGRAPHYDOCUMENTS PHOTOGRAPHY

On handwritingsOn handwritings– Sequence of crossed linesSequence of crossed lines– Writing over foldsWriting over folds– Differentiation of inks and pencilsDifferentiation of inks and pencils– PatchingPatching

On papersOn papers– Erasures Erasures – WatermarksWatermarks– elimination of paper backgroundelimination of paper background– Faded writingFaded writing– Restoring erased writingRestoring erased writing– Stamped out writingStamped out writing– burned papersburned papers

FILTERS FILTERS

is a homogeneous medium which absorbs and is a homogeneous medium which absorbs and transmits differentially light rays passing through transmits differentially light rays passing through it.it.

A color filter works in such a way that A color filter works in such a way that it will transmit its own color and absorbs other it will transmit its own color and absorbs other colors.colors.

By using filters in combination of By using filters in combination of black and white films, the photographer can black and white films, the photographer can control tonal blues to get a technically correct control tonal blues to get a technically correct condition or to exaggerate, or suppress the tonal condition or to exaggerate, or suppress the tonal differences for visibility, emphasis, and other differences for visibility, emphasis, and other effects. With color films, filters are use to change effects. With color films, filters are use to change the color quality of the exposing lights to secure the color quality of the exposing lights to secure proper color balance with film being used.proper color balance with film being used.

FILTER FACTORSFILTER FACTORSBecause filter subtract some of the Because filter subtract some of the light passing through the lens, and light passing through the lens, and increase in an exposure time or lens increase in an exposure time or lens opening is necessary. The number of opening is necessary. The number of lines that the normal exposure must lines that the normal exposure must be multiplied is called “filter factor”.be multiplied is called “filter factor”.The filter factor value depends on The filter factor value depends on film type and light source in addition film type and light source in addition to the absorption of the filter.to the absorption of the filter.

TYPES OF FILTERS IN BLACK AND TYPES OF FILTERS IN BLACK AND WHITE PHOTOGRAPHYWHITE PHOTOGRAPHY

– Correction filter- used to change the response of the Correction filter- used to change the response of the film so that all colors are recorded at approximately film so that all colors are recorded at approximately the relative brightness value seen by the eye.the relative brightness value seen by the eye.

– Contrast filter- used to change the relative brightness Contrast filter- used to change the relative brightness values so that two colors which would otherwise be values so that two colors which would otherwise be recorded as nearly the same will have decidedly recorded as nearly the same will have decidedly different brightness in the picture.different brightness in the picture.

– Haze filter- used to illuminate or reduce the effect of Haze filter- used to illuminate or reduce the effect of serial haze.serial haze.

– Neutrally density filter- used for reducing the amount Neutrally density filter- used for reducing the amount of light transmitted without changing the color values.of light transmitted without changing the color values.

– Polarizing filter- used to reduce or illuminate reflection Polarizing filter- used to reduce or illuminate reflection on highly reflective surfaces.on highly reflective surfaces.

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