Reviewer in Police Photography.1

Reviewer in Police Photography:

Reviewer in Police Photography By MELCON S. LAPINA, MSCrim 4 th Place, Criminologists Board Exams, October 1996, Manila melcon s. lapina, mscrim

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melcon s. lapina, mscrim He was able to obtain camera images on papers sensitized with silver chloride solution in 1816. He invented a photographic process which he called “heliography,” meaning “writing of the sun.” John Frederick William Herschel Joseph Nicéphore Niépce Louis Jacques Mande Daguerre William Henry Fox Talbot invented ANSWER

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melcon s. lapina, mscrim The art or science of photographically documenting a crime scene and evidence for laboratory examination and analysis for purposes of court trial. Forensic Photography Modern Photography Police Photography Technical Photography ANSWER

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melcon s. lapina, mscrim Literally means dark chamber Diaeta aquilus Anacleta atramentum Thalamus attratus Camera obscura ANSWER

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melcon s. lapina, mscrim A light tight box, with a means of forming the image (lens), holding sensitized materials (film holder), and with a means of controlling the amount of light that reach the film. Shutter Aperture Camera Lens ANSWER

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melcon s. lapina, mscrim The best way to determine the entire coverage of the camera is to look behind the lens of the camera. In this manner, the object can be framed properly and recorded on the film. This type of camera eliminates the problem on parallax error. Single-Lens Reflex Twin-Lens Reflex Press Type Camera Viewfinder Type ANSWER

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melcon s. lapina, mscrim The difference between the image seen by the viewing system and that recorded on the film. Problems occur as the subject moves closer to the taking lens when using Twin-Lens Reflex (TLR) cameras. Aberration Shutter error Diaphragm error Parallax error ANSWER

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melcon s. lapina, mscrim The object to be photographed looks double when the focusing control is not in proper distance… Coincidence Rangefinder Scale-Bed Type Split-Type ANSWER

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melcon s. lapina, mscrim Functions much like the iris of the eye—it controls the effective diameter of the lens opening. Diaphragm Focusing Shutter Lens ANSWER

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melcon s. lapina, mscrim A lens with one convex and one concave side is convex-concave. Biconcave Biconvex Meniscus Plano-Convex ANSWER

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melcon s. lapina, mscrim A lens aberration in which off-axis light rays focus as different distances when they pass through different areas of the lens. Astigmatism Chromatic aberration Spherical aberration Coma ANSWER

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melcon s. lapina, mscrim Lens with focal lengths greater than 50mm. Standard lens Telephoto lens Wide-angle lens Zoom lens ANSWER

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melcon s. lapina, mscrim The material necessary to produce a positive print is Sensitized paper Film Emulsion Filter ANSWER

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melcon s. lapina, mscrim A homogenous medium, which absorbs and transmits differentially light rays passing through it. Sensitized paper Filter Film Emulsion ANSWER

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melcon s. lapina, mscrim A part of this electromagnetic spectrum that creates the sensation of light when it falls on the human eye. Visible light UV light X-rays Infrared light ANSWER

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melcon s. lapina, mscrim Objects that caused absorption are Opaque Translucent Fluorescence Transparent ANSWER

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melcon s. lapina, mscrim Object in open space casts a deep and uniform shadow rainy sunlight bright sunlight hazy sunlight dull sunlight ANSWER

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melcon s. lapina, mscrim The process of removing unexposed silver halides remaining in the emulsion after the first stage of development of the latent image. stop bath fixation development washing and drying ANSWER

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19 melcon s. lapina, mscrim A developer for film. Dektol D-76 Hypo Glacial acetic acid ANSWER

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melcon s. lapina, mscrim The so-called camera in reverse. Contact printer Enlarger Projector Magnifier ANSWER

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Photographs are being used in police work to deter would-be offenders in committing crime. Identification purposes Recording actions of offenders For crime prevention Public information 21 melcon s. lapina, mscrim ANSWER

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melcon s. lapina, mscrim He was able to obtain camera images on papers sensitized with silver chloride solution in 1816. He invented a photographic process which he called “heliography,” meaning “writing of the sun.” John Frederick William Herschel Joseph Nicéphore Niépce Louis Jacques Mande Daguerre William Henry Fox Talbot invented

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PERSONALITY CONTRIBUTION Joseph Nicéphore Niépce Heliography – writing of the sun. Louis Jacques Mande Daguerre Daguerreotype – photograph on a silver or a silver-covered copper plate; positive image. Fixation is permanent by hypo. William Henry Fox Talbot Calotype – paper negative with light sensitive compounds on the surface. Fixation is partial. John Frederick William Herschel Coined photography . Applied terms negative and positive to photography. Frederick Scott Archer Collodion process – preceded the modern gelatin emulsion. Richard Leach Maddox Lightweight gelatin negative plates George Eastman Eastman Kodak Company & roll of film 23 melcon s. lapina, mscrim

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24 melcon s. lapina, mscrim PERSONALITY CONTRIBUTION Alhazen Described camera obscura. JM Petzval Designed the first lens specifically for photographic use Geronimo Cardano Fitted a biconvex to the camera obscura . Thomas Sutton Patented the first single-lens reflex. Vioglander Produced a lens for the use in the first all-metal unitized camera. Daniel Batbaro Suggested the use of diaphragm to sharpen the image. Proceed to Next Question

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melcon s. lapina, mscrim The art or science of photographically documenting a crime scene and evidence for laboratory examination and analysis for purposes of court trial. Forensic Photography Modern Photography Police Photography Technical Photography

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26 melcon s. lapina, mscrim DEFINITION OF TERMS CATEGORY DESCRIPTION Etymological/Literal To write with light. Gr. Phos – light & Graphia – write Modern Definition Reproduction of images: light, sensitized materials, camera and its accessories, and the chemical processes. Technical/Legal Chemical, thermal, electrical or electronic recording of the images of scenes, or objects thru XUVI. Police Photography Photography applied to police work. Forens ic Photography Documenting crime scene & evidence for laboratory examination and court trial. Proceed to Next Question

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melcon s. lapina, mscrim Literally means dark chamber Diaeta aquilus Anacleta atramentum Thalamus attratus Camera obscura

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Latin veiled chamber or dark room An optical device in drawing or entertainment. 28 melcon s. lapina, mscrim CAMERA OBSCURA Proceed to Next Question

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melcon s. lapina, mscrim A light tight box, with a means of forming the image (lens), holding sensitized materials (film holder), and with a means of controlling the amount of light that reach the film. Shutter Aperture Camera Lens

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Light-tight box – devoid of light Lens – focusing rays of light Film holder Shutter Viewing system Film advancer Shutter speed Lens aperture Focusing mechanism 30 melcon s. lapina, mscrim CAMERA Other parts Basic parts Proceed to Next Question

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melcon s. lapina, mscrim The best way to determine the entire coverage of the camera is to look behind the lens of the camera. In this manner, the object can be framed properly and recorded on the film. This type of camera eliminates the problem on parallax error. Single-Lens Reflex Twin-Lens Reflex Press Type Camera Viewfinder Type

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Type Description Viewfinder Type Smallest & simplest type; a.k.a. instamatic; suffers parallax error Single Lens Reflex Looking behind the lens of the camera; eliminates parallax error Twin Lens Reflex Type Two lenses: viewing and focusing lens, & taking lens; suffers parallax error View or Press Type Biggest and most sophisticated; not for candid & action photography Special Cameras Polaroid, panoramic cameras, aerial cameras, miniature and ultra-miniature cameras, digital cameras 32 melcon s. lapina, mscrim Major Types of Camera Proceed to Next Question

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melcon s. lapina, mscrim The difference between the image seen by the viewing system and that recorded on the film. Problems occur as the subject moves closer to the taking lens when using Twin-Lens Reflex (TLR) cameras. Aberration Shutter error Diaphragm error Parallax error Proceed to Next Question

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melcon s. lapina, mscrim The object to be photographed looks double when the focusing control is not in proper distance… Coincidence Rangefinder Scale-Bed Type Split-Type This topic discusses about control of camera.

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Type Description Focusing Setting of proper distance in order to form sharp image. Diaphragm Usu. serves as aperture stop, & controls aperture; like iris of eye. Shutter Barriers of rays of light 35 melcon s. lapina, mscrim Control of Camera

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36 melcon s. lapina, mscrim Control of Camera Type Description Rangefinder Type For viewfinder, instamatic camera and 35mm cameras: 1. coincidence – object appears double when out of focus; 2. split – object appears split when out of focus. Ground Glass Type Object appears blurred when out of focus. Scale Bed Type Focusing is made by calculating or estimating the distance of object to be photographed. Focusing ring is adjusted to corresponding estimated distance. Three Types of Focusing Proceed to Next Question Coincidence Type Out of Focus In Focus Split Type Out of Focus In Focus

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melcon s. lapina, mscrim Functions much like the iris of the eye—it controls the effective diameter of the lens opening. Diaphragm Focusing Shutter Lens

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Diaphragm Characteristics: A.k.a. Lens Opening or Aperture Size of aperture: measured by f/numbers or f/stops Ratio of f/# to aperture: larger number of f/# : smaller aperture. Small aperture: increased depth of field – nearest and farthest object in the same sharpness. 38 melcon s. lapina, mscrim Control of Camera

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Shutter Characteristics Allows light to pass for a determined period of time. Purpose: Expose photographic film, light-sensitive electronic sensor to light. Shutter Speed . About exposure time, the effective length of time a shutter is open. 39 melcon s. lapina, mscrim Control of Camera There are factors to consider in using this control. Some of them are: Factor s The light sensitivity of the film, which is determined through its ISO; The lighting condition; The motion of the subjects on different angles; and The purpose of the photographs to be taken, etc.

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Shutter is expressed in a fraction of a second. The different shutter speeds are: 1, 2 or 1/2 sec, 4 or 1/4 sec, 8 or 1/8 sec, 15 or 1/15 sec, 30 or 1/30 sec, 60 or 1/60 sec, 125 or 1/125 sec, 250 or 1/250, 500 or 1/500 sec, 1000 or 1/1000, 2000 or 1/2000. 40 melcon s. lapina, mscrim Control of Camera

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Camera shutters often include one or two other settings for making very long exposures: B (for bulb ) — keep the shutter open as long as the shutter release is held. T (for time ) — keep the shutter open until the shutter release is pressed again. 41 melcon s. lapina , mscrim

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Both control the amount of light reaching the film. Aperture Shutter Speed Lens opening Time shutter is open Smaller opening Longer time 42 melcon s. lapina, mscrim Exposure : Aperture & Shutter Speed COMPENSATION

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As discussed, exposure is the combination of aperture and shutter speed. Thus, it is defined as the product of the total light intensity and the length of time it strikes the emulsion. Exposure priority refers to giving precedence of particular camera control – aperture or shutter – over the other depending on the purpose of the photographer. Ex. Aperture priority – photographer sets first the aperture and adjusts the shutter speed to compensate. 43 melcon s. lapina, mscrim Exposure Priority Aperture Priority Purpose Aperture Shutter Speed Result Show entire scene Small Slow Good depth of field. Select or highlight particular object in scene Big Fast Object selected – sharply focused. Foreground and background – poor. Shutter Speed Priority Purpose Shutter Speed Aperture Result Maximizing sharpness Slow Small Much of scene is sharp. Taking nightscapes Very slow Very small Cityscapes at night are clearly seen using available light. Freezing action in mid-air Fast Big Action is frozen. Maximizing Sharpness Nightscapes Frozen in Mid-Air Proceed to Next Question

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melcon s. lapina, mscrim A lens with one convex and one concave side is convex-concave. Biconcave Biconvex Meniscus Plano-Convex This topic discusses about LENS.

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A lens is an optical device with perfect or approximate axial symmetry which transmits and refracts light, converging or diverging the beam. 45 melcon s. lapina, mscrim The Lens Proceed to Next Question

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melcon s. lapina, mscrim A lens aberration in which off-axis light rays focus as different distances when they pass through different areas of the lens. Astigmatism Chromatic aberration Spherical aberration Coma This topic discusses about inherent lens defects or aberrations .

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Defect Description Spherical aberration Light passing through near the central part of a converging lens is bended more sharply than those rays falling in the edge. The rays coming from the edges are focused on a plane nearer the lens than those coming from the central part. 47 melcon s. lapina, mscrim Lens Aberrations Defect Description Spherical aberration Light passing through near the central part of a converging lens is bended more sharply than those rays falling in the edge. The rays coming from the edges are focused on a plane nearer the lens than those coming from the central part. Defect Description Coma Another form of spherical aberration but is concerned with the light rays entering the lens obliquely. The defect is noticeable only on the outer edges and not on the central part of the lens. Circular objects reproduced at the corners of the negative are comet-like form. Defect Description Curvature of Field The image formed by a lens comes to a sharper focus in curved surface than a flat surface. The correction of this defect is similar to spherical aberration and coma. Defect Description Distortion Incapable of rendering straight lines correctly – either horizontal or vertical lines in an object. Caused by the placement of the diaphragm. Barrel distortion - If the diaphragm is placed in front of the lens, straight lines near the edges of the object tends to bulge outside. Pincushion distortion – If the diaphragm is placed behind the lens, straight lines near the edges tends to bend inward. Remedied by placing the diaphragm in between the lens component and the two opposite distortions will neutralize each other. Barrel Distortion Defect Description Chromatic Aberration The inability of the lens to bring photographic rays of different wavelengths to the same focus. Ultraviolet rays – bent the most Infrared rays – bent the least Reduced by utilizing compound lenses made up of single lens made up of glass of different curvatures. Defect Description Astigmatism The size of image produced by photographic rays of one wavelength is different from the size produced by another. Size of the image increases as the wavelength of the rays decreases. Color photography – rainbow colored fringes around edges of objects B&W Photography – slight blue. Classic example of astigmatism. Left wheel: no astigmatism. In the presence of astigmatism (middle and right wheels) one discriminates between the sagittal and tangential foci. Proceed to Next Question

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melcon s. lapina, mscrim Types of Lenses ( accdg to degree of correction to lens aberration ) Type Description Achromatic lens corrected for chromatic aberration Rapid-rectilinear lens corrected for distortion Anastigmat lens corrected for astigmatism as well as the other lens defects Apochromatic lens also corrected for astigmatism but with higher degree of correction to color Proceed to Next Question

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melcon s. lapina, mscrim Lens with focal lengths greater than 50mm. Standard lens Telephoto lens Wide-angle lens Zoom lens This topic discusses about focal length. Focal Length It is the distance measured from the optical center of the lens to the film plane when the lens is set or focused at infinity position or far distance. Focal Length Characteristics Measure of the light-bending power of a lens. Measured in millimeters (mm). Longer focal length - Narrower the angle of view - Larger the objects appear in the viewfinder without need to go move closer. Focal Length Type Characteristics Standard 50mm View that it gives is similar to that of human eye . Wide-Angle Shorter focal length Wider angle of view Telephoto Greater than 50mm Narrower angle of view Zoom Lens Variable focal length

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50 melcon s. lapina, mscrim Factors Affecting Depth of Field Proceed to Next Question

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melcon s. lapina, mscrim The material necessary to produce a positive print is Sensitized paper Film Emulsion Filter This topic discusses about films and papers Two General Types of Films Black & White Emulsion Gray/Anti-Halation Backing Film Base Color Film Multi-layer emulsion coated on the same support or base. Emulsion a suspension of a sensitive silver salt or a mixture of silver halides in a viscous medium (as a gelatin solution) forming a coating on photographic plates, film, or paper. Gray Placed between the light-sensitive emulsion and the tough film base, or sometimes on the back of the film base. Absorbs light by and into opaque anti-halation layer. Prevents re-exposing of film Being washed from film during processing. Film Base Transparent substrate Support medium for the photosensitive emulsion atop it. Accounts for the thickness of film. Types: cellulose nitrate, cellulose acetate and polyethylene trephthalate polyester (Kodak trade-name: ESTAR) Characteristics of B & W Films Emulsion Speed Spectral Sensitivity Granularity or Graininess Emulsion Speed ASA (American Standards Association) rating. This is expressed in arithmetical value. DIN (Deutsche Industrie Normen ) rating, which is expressed in logarithmic value. ISO (International Standards Organization) rating. This is expressed in the combined arithmetical and logarithmic values. Spectral Sensitivity Blue sensitive film – sensitive to UV rays and blue color only Orthochromatic film – sensitive to UV rays, to blue and green color. It is not sensitive to red color. Panchromatic film – sensitive to UV radiation to blue, green, and red light or all colors. Infra-red film – sensitive to UV rays, to blue, green, red light and infrared rays. Granularity : size of metallic silver grains that are formed after development of an exposed film. Points to remember Lower emulsion speed , finer grains. Higher emulsion speed, bigger grains Film developer – finer grain Paper developer – bigger grain Main Types of Color Film Color negative film Forms a negative (color-reversed) image when exposed Permanently exposed during developing E.g. Kodacolor Color reversal film A.k.a. slide film Forms a negative image when exposed Reversed to a positive image during developing Projected onto a screen. E.g. Kodachrome Ways of Exposing Photographic Paper Contact printing Placing negative in contact with paper directly to produce contact print Enlarging Using enlarger in order to create latent image Exposing in specialized camera Producing photographic negative Photograms Placing objects upon it Photographic papers are subsequently developed using the gelatin-silver process to create a visible image. Characteristics of a Photographic Paper Chloride paper has a slow speed and is suited for contact printing. Bromide paper has a fast speed and is recommended for projection printing or enlarging. Chloro -bromide paper is a multi-speed and could be used in both contact printing and enlarging. Proceed to Next Question

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melcon s. lapina, mscrim A homogenous medium, which absorbs and transmits differentially light rays passing through it. Sensitized paper Filter Film Emulsion FILTERS TYPES OF FILTERS Light Balance Filter to change the color quality of the exposing light in order to secure proper color balance for artificial light films. Color Compensating Filter to change the over-all color balance of photographic result obtained with color films and to compensate for deficiencies in the quality of exposing energy. Neutral Density Filter when the light is too bright to allow the use of desired f-number or shutter speed with a particular film. Polarizing Filter to reduce or minimize reflections on subjects like water glass, and highly polished surfaces. Proceed to Next Question

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melcon s. lapina, mscrim A part of this electromagnetic spectrum that creates the sensation of light when it falls on the human eye. Visible light UV light X-rays Infrared light Light: Its Characteristics & Sources Light is a form of electromagnetic energy that can be explained in the following: wavelength , frequency and energy . Wavelength Light is traveling like a wave, e.g. ripples in surface of water. Parts: 1. Crests – peaks, 2. Troughs – valleys Wavelength – distance between two consecutive peaks (or troughs) Greek symbol: letter λ (lambda) Visible Light Measured in nanometers; 1nm = 1 billionth of meter ( 10 -9 meters). 400 – 700 nm Rainbow Colors Violet 400 to 440nm Blue 440 to 490nm Green 490 to 540nm Yellow 540 to 590nm Orange 600 to 650nm Red 650 to 700nm Photographic Rays of Modern Photography X-rays 1 to 30 nm Ultra-Violet Rays 30 to 400 nm Visible Light 400 to 700 nm Infrared Rays 700 to 1,000+nm White is the presence of all colors. Black is the absence of all colors or the absence of light. Light travels in a straight line at 186,000 miles/second. However, when light comes in contact with an object, it may be bended in the following manner: BENDING OF LIGHT Type Subtype Description Reflection Specular or Regular Reflection Reflecting surface – very smooth Diffuse or Irregular Reflection Reflecting surface – rough or granular Refraction Change in direction of wave due to chang e in speed Observed when wave passes from one medium to another Diffraction Apparent bending of waves around small obstacles and spreading out of waves past small openings. Bending of light when it hits sharp edge of opaque object. Specular or Regular Reflection Diffuse or Irregular Reflection The straw seems to be broken, due to refraction of light as it emerges into the air. Examples of Diffraction The closely spaced tracks on a CD or DVD act as a diffraction grating to form the familiar rainbow pattern we see when looking at a disk; The hologram (a picture that changes when looked at from different angles ) on a credit card; Proceed to Next Question

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melcon s. lapina, mscrim Objects that caused absorption are Opaque Translucent Fluorescence Transparent This t opic talks about the different kinds of objects that light may come in contact with. Kinds of Objects Kind Description Transparent objects Allows light to pass through; object on the other side may be clearly seen. Translucent objects Allows light to pass but sufficiently diffused; objects on the other side may not be clearly distinguished. Some may be recognizable but detail and outline are obscured. Opaque objects Greatly diffuse the light; the object on the other side is very difficult if not impossible. Proceed to Next Question

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melcon s. lapina, mscrim Object in open space casts a deep and uniform shadow rainy sunlight bright sunlight hazy sunlight dull sunlight This topic discusses about SOURCES OF LIGHT. SOURCES OF LIGHT Natural Light Source Moonlight, lightning, starlight, sunlight, etc. Artificial Light Source Man-made; divided into: 1. continuous radiation and 2. short duration. Natural Light Source (by Sunlight) Bright Sunlight Objects in open space cast a deep and uniform or distinct shadow. Hazy Sunlight Objects in open space cast a transparent shadow. Dull Sunlight Objects in open space cast no shadow. Types of Dull Sunlight Cloudy bright Objects in open space cast no shadow but objects at far distance are clearly visible. Cloudy dull Objects in open space cast not shadow and visibility of distant objects are already limited. Artificial Light Source Artificial light sources most useful to police work are FORENSIC LIGHT SOURCES. FORENSIC LIGHT SOURCES UV Lamp LASER – Light Amplification through Simulated Emission of Radiation. Alternative Light Sources Alternative Light Sources Proceed to Next Question

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melcon s. lapina, mscrim The process of removing unexposed silver halides remaining in the emulsion after the first stage of development of the latent image. stop bath fixation development washing and drying This topic discusses about CHEMICAL PROCESSING of FILM. Chemical Processing of Film Black & White Processing Development, stop-bath, and fixation. Color Processing Development, stop-fix, and stabilizer. Development – the conversion of latent image in an emulsion into visible image. DEVELOPMENT B & W Emulsion Reducing exposed silver halide crystals (black silver) into metallic silver. (Same reaction is found in photographic papers.) Color Emulsion Developed silver is replaced with cyan, yellow, and magenta dye. STOP-BATH The purpose of the stop bath is to halt the development of the film, plate, or paper by either washing off the developing chemical or neutralizing it. FIXATION The fixer removes the unexposed silver halide remaining on the Photographic film or photographic paper, leaving behind the reduced metallic silver that forms the image, making it insensitive to further action by light. Without fixing, the remaining silver halide would quickly darken and cause severe fogging of the image . Salts Used in Fixation The most common salts used are sodium thiosulfate - commonly called hypo - and ammonium thiosulfate , commonly used in modern rapid fixer formula. Film Processing : How Done Carried out in trays, tanks, or mechanized equipment. Panchromatic materials – handled in total darkness. Blue films, orthochromatic films and printing papers – handled under a safelight. Equipment for Film Processing Tank or tray Timer Developing reel Funnel Opener for film cartridge (pliers) Photographic sponge Scissors to cut the tongue of the film Film clips for drying Thermometer glass or plastic bottles (gallon size) for storing mixed solutions. Proceed to Next Question

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57 melcon s. lapina, mscrim A developer for film. Dektol D-76 Hypo Glacial acetic acid This takes up the formulation of developer , stop-bath and fixer . Typical Component of Developer: Solvent (water) Developing agent Preservative Accelerator or activator Restrainer D-76 Film Developer formula 1. Water 52 0 C or 125 0 F - 750 ml 2. Elon - 2 gm 3. Hydroquinone - 5 gm 4. Sodium Sulfite - 100 gm 5. Borax (granules) - 2 gm 6. Water to make - 1 li DEKTOL – Paper Developer 1. Water 52 0 C or 125 0 F - 500 ml 2. Elon - 311 gm 3. Hydroquinone - 12 gm 4. Sodium Sulfite - 4.5 gm 5. Sodium carbonate - 67.5 gm 6. Potassium bromide - 1 gm 7. Water to make - 1 li STOP-BATH Stop-bath can be plain water only with 28% glacial acetic acid. FIXING BATH FORMULA 1. Water 2. Dissolving agent 3. Preservative 4. Neutralizers 5. Hardeners Typical Fixing Formula: 1. Water 52 0 C or 125 0 F - 600 ml 2. Hypo - 240 gm 3. Sodium sulfite - 15 gm (anhydrous) 4. Acetic Acid (28%) - 480 ml 5. Boric Acid (crystals) - 7.5 gm 6. Potassium alum - 15 gm (fine granular) 7. Water to make - 1 li Proceed to Next Question

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melcon s. lapina, mscrim The so-called camera in reverse. Contact printer Enlarger Projector Magnifier This topic deals with photographic printing . Types of Photographic Printing Contact Printing Photographic materials are exposed by pressing in contact with the negative being reproduced. Projection Printing or Enlarging The image in a negative is optically projected or enlarged onto a print material for exposure to produce a picture image. The main equipment is Enlarger, the so-called camera in reverse . EQUIPMENT FOR PAPER DEVELOPING Three plastic trays – one each for the developer, stop-bath, and the fixer. (The size of the tray is determined by the largest prints size). Timers Metal, plastic, or bamboo tong preferably with rubber ends to hold the prints. Paper cutter Rubber (surgical) hand gloves. A bigger tray or tank for washing prints. Proceed to Next Question

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Photographs are being used in police work to deter would-be offenders in committing crime. Identification purposes Recording actions of offenders For crime prevention Public information 59 melcon s. lapina, mscrim This topic discusses about application of photography to police work . GENERAL APPLICATION Identification purposes For court exhibits Recording and preserving of evidences For crime prevention Discovering and proving of evidences not readily seen by the naked eye. Public information Recording action of offenders Police training SPECIFIC APPLICATIONS Identification Photographs Crime-Scene Photography

CRIME SCENE PHOTOGRAPHY:

CRIME SCENE PHOTOGRAPHY What crime scene photography can give: It seeks to establish a visual record of the condition of the scene and the items present in it. It leads the viewer from the overall perspective to the details of specific objects. 60 melcon s. lapina, mscrim A crime scene photo log helps eliminate the following issues: Identification, Orientation, and Confusion Issues Crime Scene Photo Log It is a written record of photos, detailing: Administrative data. What time the photos were taken and in what order. What they show. Other pertinent details as deemed necessary. Crime Scene Photo Log Crime Scene Photo Log Case #: 02-01-0045 Date: January 13, 2002 Camera Used: Nikon F2a Time: 1830-1940 Hrs Film Type: ASA 400 Scene: 3567 Wayland Dr. Photographer: SA Brown Film Roll #: 1 Types of Crime Scene Photographs Over-all Photographs Evidence Establishing Photographs Evidence Close-Up Phtographs Overall Photographs Characteristics Exposed with wide-angle lens Typically taken by shooting from the four corners of the crime scene. Documents the condition and layout of the scene as found. These four photographs will often capture the entire scene. Eliminate issues of subsequent contamination (e.g. tracked blood, movement of items). Photographs from vantage point can be taken if four photographs are not sufficient.

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61 melcon s. lapina, mscrim Shooting the Four Corners Crime Scene Photo # 1 Photo # 2 Photo # 3 Photo # 4

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62 melcon s. lapina, mscrim Overall Photo #1 Overall Photo #2 Overall Photograph Example Overall Photo #3 Overall Photo #4

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Characteristics Typically exposed with a 50mm lens. Most overlooked photograph in crime scene work. Frames the item of evidence with an easily recognized landmark. It is not intended to show details, simply to frame the item with a known landmark in the scene. Visually establishes the position of the evidence in the scene. It goes hand in hand with close-up photograph. 63 melcon s. lapina, mscrim Evidence Establishing Photos

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64 melcon s. lapina, mscrim Use of Establishing Photo Where is this item in the scene? The blue background by itself might indicate a number of locations.

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65 melcon s. lapina, mscrim Evidence Establishing Example Evidence Establishing Photograph

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66 melcon s. lapina, mscrim Evidence Close-up Photographs Evidence close-up photographs are exposed with a "macro" lens (50mm, 55mm or 105mm). Their function is to allow the viewer to see all evident detail on the item of evidence. You have to get close and fill the frame with the evidence itself. They are taken with and without a scale.

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67 melcon s. lapina, mscrim Evidence Close-up Example Taken both with and without a scale of reference. Get close and fill the frame of the camera.

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68 melcon s. lapina, mscrim Very important when taking photos of small items, whose detail may affect another analysis. Ensure a good focus, make the picture sharp. Evidence Close-up Example

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69 melcon s. lapina, mscrim Photograph Methodology Document the entire scene in-situ as soon as possible using overall photographs. Photograph all fragile evidence as soon as possible. In the documentation stage, photograph all known evidence using evidence establishing and evidence close-up photos. As items are discovered in later stages, return and document them fully, including additional overall photographs if needed.

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70 melcon s. lapina, mscrim Photograph Methodology Create photographs that fully demonstrate the results of additional examinations (e.g. latent prints, bloodstain pattern analysis, trajectory analysis). Always use a film roll reference card on the first shot of each roll to demonstrate admin data. Always use a crime scene photo log.

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Chromatic Difference of Magnification – The inability of the lens to produce image sizes of objects with different colors. Depth of Focus – It is the distance toward and away from the film that the lens can be moved at a given f-value and the object still appears in interior. 71 melcon s. lapina, mscrim Some Important Terms

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Hyperfocal Distance – The nearest space at which a lens is focused with a given particular diaphragm opening which will give the maximum depth of field. Macrophotography – The photography of a subject so that the final image is either unmagnified or magnified to no more than 10 times the object. 72 melcon s. lapina, mscrim Some Important Terms

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73 melcon s. lapina, mscrim Some Important Terms Microphotography – It is the facsimile of photographs in which the image of an object is reproduced much smaller than it actually is. Photomicrography – Photography showing initial magnifications when the camera is used in relation with a microscope.

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Photomacrography – Making large pictures of small subjects by using a short-focal-length lens on a long-bellows camera. Relative Aperture – The light gathering power of the lens, expressed in the F-number system. 74 melcon s. lapina, mscrim Some Important Terms