How Long Does It Take to Do Photography at Crime Scene
Evidence Photography — At the Crime Scene
Steven Staggs
© 2014 from the book Crime Scene and Evidence Photography, 2nd Edition
Overview
Several types of evidence are commonly found at criminal offense scenes. Each item of show must be documented photographically, showing its location and appearance. In the previous chapter the basic concepts of evidence photography were discussed. This affiliate provides more specialized techniques for photographing evidence usually found at crime scenes.
As you study this chapter, be aware that many of the techniques in this affiliate can also be applied in a laboratory setting. For example, fingerprints on an detail that will be collected as evidence may either be photographed at the scene before packaging or later on in the laboratory. Several factors may be considered in this instance. Information technology may be safer to photograph the fingerprint at the scene if in that location is a chance the fingerprint will be damaged when the evidence is transported to the laboratory, or it may be more than effective to photograph the fingerprint in the laboratory due to the specialized lighting available on a copy stand. It will be upwardly to the law-breaking scene photographer to determine which would be the best class of action for each item of bear witness.
Footwear Impressions
Footwear and tire impressions are perchance the most disregarded prove at a criminal offence scene. When impressions are nerveless information technology is possible that identifications tin exist made linking a suspect or vehicle to the crime. Impression show can be nerveless by casting (filling the impression with a compound that hardens and retains the shape and characteristics of the impression) and with photography. Photographs of impressions are often used to make positive identifications, only casting of impressions provides the best show. This is because impressions are 3–dimensional and casting preserves three–dimensional prove. The depth of tread and imperfections on the sides of the tread are preserved with casting. At major crime scenes impressions should exist photographed before they are casted. Photography is washed start because casting the impression will destroy the original impression and eliminate the ability to photograph the impression afterward. Also, photographs of an impression are taken in example there is a problem with the cast. If the casting fails, the photograph may be used to make an identification.
At small criminal offence scenes impressions are usually photographed without casting. If the impression is properly photographed positive identification linking a doubtable or vehicle to the law-breaking is possible.
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When taking photographs of footwear or tire impressions begin with a photograph to show where the impression is located in the crime scene. Information technology is important to include a recognizable landmark in the photograph so the location of the impression is understood. If the impression is nigh a landmark, such as in a flowerbed at the corner of a house, a mid–range photograph probably would be adequate to prove the location of the impression. If the impression is farther away from a recognizable landmark, such equally an impression on a dirt driveway twenty yards from the house, additional photographs would be necessary. An overview photograph showing the driveway with the house in the background would be followed with a mid–range photograph of the impression on the driveway. It may be necessary to include an prove mark in both the overview and mid–range photographs to clearly testify the location of the impression in the photographs.
There may exist times where it is not possible to show the exact location of an impression with photographs. The impression may exist located in an expanse with no recognizable landmarks nearby, such as in an open area of the desert. In this case the apply of a GPS device (to give location) and a compass (to indicate direction the evidence is oriented) may be the just way to document the exact position of the impression. In such a instance you could tape the GPS information in your notes, and in the photo of the impression include an pointer that is oriented to betoken north.
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After photographically documenting the location of the impression you must take close–up photographs to bear witness the item of the impression. If yous are using a film photographic camera it is best to photograph impression evidence with blackness–and–white film. Blackness–and–white picture provides more contrast and particular than nigh color films.
When photographing with a digital photographic camera all photographs should be taken as RAW file images in color manner. RAW files are uncompressed and will capture more than item than JPG or TIF file images. By photographing in color, subtle tones that could exist lost when photographing in blackness–and–white fashion will be captured. Later the color digital photograph can be inverse into grayscale in a plan such as Adobe® Photoshop®.
To take a close–up photograph of an impression, place the camera on a tripod and position the photographic camera and so the camera's film aeroplane is parallel with the impression. This will minimize distortion in the photo. An angle finder can be used to measure the angle of the impression and then, by placing the bending finder on the photographic camera's eyepiece, the angle of the camera can be adjusted to friction match the angle of the impression. The film plane volition then exist parallel to the impression.
Adjacent, place a scale alongside the impression. When photographing a footwear impression utilise an "50" shaped calibration. When photographing a tire impression use a long straight calibration aslope the impression. Place the scale approximately one inch away from the impression and on the same aeroplane every bit the impression. If necessary, printing the calibration into the ground until it is the same depth as the impression.
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Orientation of the impression is also of import. The direction a footwear impression faces could be important to the investigation. For example, in a residential burglary it would be important to show that the footwear impressions in a flowerbed face the window that was used by the suspect to enter the residence. Showing the orientation tin can exist accomplished with a mid–range photograph that includes the window and the impressions. If it is difficult to see the orientation of the impressions in the mid–range photograph, an pointer (indicating north) tin can be included in both the mid–range and close–up photographs.
In order to become every bit much particular recorded on the flick equally possible, your camera should exist positioned so the frame of your viewfinder is filled with the impression and scale.
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Nigh of the particular recorded in an impression photograph volition be visible due to the small shadows that appear inside the impression. The existing shadowing from daylight does non always provide the best results. The position of the sun may actually provide the to the lowest degree desirable results. If you settle for the lighting provided past the sun yous will usually accept poor quality impression photographs. In fact, information technology is necessary to take several photographs of each impression, with the lighting from unlike angles, to show all the detail within an impression.
The most effective way to insure you lot are using the all-time angles of lighting is "preview the photograph" by looking at lighting from several different angles. To exercise this, shade the impression with a large piece of paper-thin. And then, position a stiff light source, such equally a powerful flashlight, at unlike angles to find the light angles that prove the best detail in the impression. As you motility the lighting y'all will come across the results you will go by looking into your viewfinder. Then position your electronic flash at the best angles for the photographs. You lot will commonly need two people to assist y'all with this technique—ane to hold the cardboard and the other to movement the flashlight and position the electronic flash.
Another lighting technique would exist to have a series of photographs with the electronic flash or light source at six different angles. 2 photographs would exist taken from each of three directions, ane with the electronic flash positioned at a 25 degree bending and the other positioned at a 45 degree angle. You will probably want to use a lower bending for impressions in dust and for very shallow impressions, and a higher angle for deep impressions.
Impressions in snow are photographed with the aforementioned techniques detailed to a higher place. One additional event with photographing impressions in the snowfall is exposure. Remember that the camera'southward metering system provides settings for normal lighting which is 18 percent reflectance. Since the field of study matter in the photograph is virtually all white, the meter will provide exposure settings that result in an underexposed photograph. Much of the item in the photograph will be lost. When using ambience light for photographs in the snow y'all can insure authentic exposures past using an xviii per centum grey bill of fare. Position the 18 percent gray card in front end of the camera lens to obtain the correct exposure settings. Be certain the ambience lite is falling on the xviii pct gray card the aforementioned equally it is falling on your evidence. Use the settings indicated by the exposure meter for the photograph. In many cases, bracketing should as well be considered. Bracketing will provide a series of photographs at different exposures. After, the best exposures from the series of photographs tin can be used for the investigation. This applies to the overview, mid–range and close–up photographs of snow scenes and prove.
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When using an electronic flash to photograph footwear impressions in the snow it is likely your photographs will be underexposed. This is considering the automatic and TTL electronic flash systems are designed to control the duration of the flash by reading the light reflected off normal subjects. Since the snowfall volition reverberate more low-cal than a normal subject the automatic and TTL systems will usually shut off the wink before an acceptable exposure is made. The resulting photographs can exist underexposed by about two f–stops.
You tin can adjust your camera to gain dorsum the two f–stops of exposure. When using an automated photographic camera adjust the camera's exposure control setting to a setting of +2. When using a manual camera close down the lens aperture by ii f–stops (e.k. if a normal wink photo requires a f/11, modify the aperture to f/five.6). In many cases, bracketing should also be considered. Bracketing will provide a series of photographs at dissimilar exposures. After, the best exposures from the serial of photographs can be used for the investigation.
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When working with a tripod in the snow information technology is sometimes hard to steady the tripod when it tends to sink into the snow. Placing computer or sound meaty disks under the tripod legs will help stabilize the tripod. This aforementioned technique works when using tripods on mud or sand.
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Dusty footwear impressions are sometimes found at crime scenes. They can sometimes be detected by shining a stiff light source at low oblique angles beyond surfaces such as floors, doors (east.g., doubtable kicked open a door) and victims' bodies (e.g., victim was stomped to death). This type of footwear impression is best photographed with low-cal from a depression oblique angle.
Dusty footwear impressions can also be nerveless with gelatin lifters, static dust lifting materials, and electrostatic dust lifters. Each of these techniques causes the dust to adhere to the lifting medium. Once the grit impression has been lifted, the impression is normally preserved with photography. When photographing a lifted grit impression position the camera with its film plane parallel to the dust impression, place a scale on the same airplane equally the impression, and photo with lite from a depression oblique angle.
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Impressions in materials such as blood, grease and oil, which are visible with existing lite, may be photographed with ambient (existing) light or with indirect electronic flash (the wink is not pointed straight at the impression). Even so, it is ever best to "preview the photograph" by looking at lighting from several different angles every bit well as the event of ambient calorie-free. To do this, position a potent light source, such as a powerful flashlight, at different angles to find the calorie-free angles that bear witness the all-time detail in the impression. Equally you move the flashlight y'all will see the results you will get by looking into your viewfinder.
Tire Impressions
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The technique for photographing a tire impression is similar to photographing footwear impressions. However, y'all must photograph tire impressions in enough sections to show one circumference of the tire. Identify a long scale or record measure alongside the tire impression. The numbers on the scale must be large plenty to exist clearly seen in the photograph. Accept three or four overlapping photographs to show enough tire impression for one total circumference of the tire. Do not motion the scale while taking the photographs. Subsequently, the series of overlapping photo-graphs can be pieced together by matching the scale in the photographs.
When photographing tire impressions think to use the same techniques of lighting and camera and scale placement as discussed earlier for footwear impressions.
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Tool marks
Tool marks are often found at criminal offense scenes. They can be marks left from pry tools, such as crowbars and screwdrivers, marks on a doorknob left from adjustable pliers used to proceeds entry in a break-in, or other tools used in the commission of a crime. When a tool mark is nerveless it is possible that a positive identification can be made linking a tool to the law-breaking.
Tool mark prove tin can be collected by casting and by photography. Photographs of tool marks are often used to make positive identifications, only casting of tool marks yields the best show. This is because a tool mark is 3–dimensional and casting preserves 3–dimensional evidence. Casting of tool marks is done with casting putty. At major crime scenes tool marks should be both casted and photographed. At minor criminal offense scenes tool marks should be photographed fifty-fifty if it is decided not to cast the tool marks.
In some cases an item begetting a tool marker can be collected every bit evidence (e.g., a doorknob begetting marks from pliers is removed from the door and placed into testify). If the item will be collected its location should exist documented with photographs. Subsequently, close–up photographs and casting of the tool marks can be done in the laboratory.
When taking a photograph of a tool mark begin with a photograph to show where the tool marking is located in the crime scene. It may exist necessary to utilise both overview and mid–range photographs to clearly show the location of the tool mark in the photographs. If there are multiple tool marks it may be necessary to include numbered bear witness markers to differentiate one tool mark from some other.
When taking a close–up photo of a tool marking be certain to identify a calibration on the same plane as the tool mark. Self–agglutinative scales are convenient for photographing tool marks, particularly tool marks on vertical surfaces; merely a lightweight plastic scale tin can exist taped (using fingerprint record) to a vertical surface when necessary.
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Position the camera with the camera'south film airplane parallel to the tool marker prove. In order to get as much detail recorded on the pic as possible, position the camera so the frame of the viewfinder is filled with the tool mark and scale. Using a tripod helps with the positioning of the camera and steadies the camera. This is of import since depth–of–field is shallow in shut–up photographs. Precise focusing can exist fabricated with a camera mounted on a tripod.
When photographing with a digital camera all photographs should be taken in colour way. Even if the finished photograph would exist ameliorate in black–and–white information technology should still exist taken in color when using a digital camera. By photographing in colour subtle tones that could be lost when photographing in blackness–and–white mode will exist captured. Later the color digital photograph can exist changed into grayscale in a program such every bit Adobe® Photoshop®.
If photographing with film information technology is best to photograph tool marker evidence with black–and–white film. Black–and–white picture provides more contrast and particular than about color films.
Proper lighting will prove particular in the tool marker. Do not try to photograph tool marks with an electronic flash positioned on the camera. If y'all do you will normally get reflection from the object you are photographing. The reflection will obscure detail. The all-time style to lite tool marks is with oblique lighting. Oblique lighting will reduce reflections and show greater detail by creating small shadows inside the tool marks. The nearly effective way to insure you are using the all-time angles of lighting is "preview the photo" by looking at lighting from several different angles. To do this, position a potent lite source, such as a flashlight, at different angles to discover the lite angles that reveal the all-time detail in the tool mark. As you lot motion the lighting you will come across the results you will get by looking into your viewfinder. At this point yous can photograph the tool mark using the lighting from the flashlight or you can position your electronic flash at the best angles for the photographs.
Fingerprints
Perhaps the nearly common class of evidence collected at criminal offense scenes is fingerprints. Fingerprints should be photographed before they are collected on major cases or if the latent may exist destroyed when lifting. Occasionally, a latent impress tin can exist visible or developed on a surface but cannot be lifted (e.thou. a fingerprint in blood). In such a instance photographing the latent is the merely mode to certificate the prove.
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Photography tin can also be used to bring out detail in a latent. Through the utilise of lighting, filters, processing controls, and enhancement (in a plan such every bit Adobe® Photoshop®) a faint latent fingerprint tin be enhanced. This is mostly done by building contrast between the latent and its background.
Digital images
When photographing with a digital camera all photographs should exist taken in color manner. Even if the finished photograph would be ameliorate in black–and–white it should still be taken in color when using a digital photographic camera. By photographing in colour subtle tones that could be lost when photographing in blackness–and–white mode will be captured. Later the color digital photograph can exist changed into grayscale in a programme such as Adobe® Photoshop®.
When photographing prove containing fine detail with a digital camera it is highly recommended the images be captured as RAW files. Raw files are unprocessed information directly from the imaging sensor and saved in their true, 12 or 14 chip color depth. RAW files are read-only files and must exist converted to another type after they are processed. Information technology is recommended RAW files be enhanced (in a program such every bit Adobe® Photoshop®) and and so saved as TIF files.
Film
Well–defined fingerprints tin usually be photographed with color flick. However, blackness–and–white film provides greater contrast than color film and is preferred for latent print photography. The post-obit is a list of a few black–and–white films that are suitable for latent fingerprint photography.
Normal contrast photographs tin be taken using a professional black–and–white flick such every bit Kodak T–MAX or Ilford Delta Professional films. For all-time results develop Kodak T–MAX movie in T–MAX programmer and process Ilford Delta Professional films in ILFOTEC HC programmer. A little higher dissimilarity can be obtained by increasing the picture development time by twenty-five percent.
Some blackness–and–white films can be processed in color processing machines. Yous can accept these films to color photo labs for processing in their color equipment. Kodak Professional BW400CN and Ilford XP–ii Super are black–and–white films that are processed in color processors. They each have an ISO of 400, are fine grain with skillful sharpness and resolution, and are processed in C–41 color chemistry.
In black–and–white photographs all colors become shades of grayness. This can be a problem when two colors become nearly the same shade of gray in a photograph. However, colored filters can exist used to increase contrast between colors in black–and–white photographs. Color filters can build contrast by either lightening or darkening the latent print, or past lightening or darkening the background. To lighten a color, the color filter closest to the color is used. To darken a color, the opposite color filter is used. (See the following two tables for data on using filters with black-and-white film.)
Blackness and White Contrast Filters
Objective: To increment contrast between colors that would unremarkably photo as near the same shade of grey.
Light Data — White low-cal is made up of a mixture of the main colors—crimson, green and blue. In theory red, greenish, and blue light sources simultaneously projected on the aforementioned area will be white. Red and dark-green light mixed together makes yellowish. Green and blue light mixed is cyan. Blue and ruddy low-cal mixed is magenta.
Light Transmission Constabulary — The filter transmits its ain colour (lightened in the print) and absorbs (subtracts) its complementary colour (darkened in the print).
Selecting Blackness-and-White Films and Filters
to Obtain Contrast Between Colors
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For instance, a black powdered latent on a bluish background would be difficult to see in a blackness–and–white photo. However, the latent print tin be enhanced by causing the background to lighten by using a blue filter. A ninhydrin developed latent on the back of U.Due south. currency tin exist enhanced in two means by using a green filter. The green ink in the currency is lightened (the groundwork is lightened) and the violet colored ninhydrin developed latent fingerprint is darkened.
Procedures in Photographing Fingerprints
Plant the Location of the Fingerprint
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If you are going to photograph a fingerprint, the location of the fingerprint must be established. While you could use mid–range photographs to show where each fingerprint is located in the scene, the employ of numerous mid–range photographs to show the locations of pocket-size items tin go confusing. A improve technique is to forego the mid–range photographs and use the diagram and notations on the latent impress menu to identify the original location of each fingerprint. This tin can exist done past including a scale in the close–up photograph of each fingerprint. On the scale write the evidence item number that will be used on the latent print card. Exist sure the calibration and the detail number announced in the close–up photograph of the fingerprint. Then the location of the fingerprint in a photo can exist related to a latent print menu on which the fingerprint's location was diagramed and described.
Shut–up Photograph
While in that location are specialized cameras designed for fingerprints, a 35 mm or good quality digital camera with a macro lens or close–upwardly accompaniment tin can exist used for fingerprint photography. Using a tripod helps with the positioning of the camera and also steadies the photographic camera. This is important since depth–of–field is shallow in close–up photographs. Precise focusing can exist made with a camera mounted on a tripod. Photo the latent with the photographic camera'south film airplane parallel to the fingerprint surface. In order to become every bit much detail recorded on the film equally possible, position the camera so the frame of your viewfinder is filled with the fingerprint and scale.
Exposure
Some fingerprints tin can be photographed using ambient (existing) light. Ambient low-cal exposures of fingerprints with normal contrast can be exposed using the camera'due south exposure system if the fingerprint and its background are of normal reflectance. If the background is lighter or darker than normal, and so the exposure should be determined past metering off an 18 pct grayness card. For example, when photographing a black powdered fingerprint on a white background, the camera will normally underexpose the photograph and detail in the photograph will be lost. This is because virtually of the image is white and reflects more light than a normal background. In such a situation you should meter off an xviii percent gray menu to determine the correct exposure settings.
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Artificial calorie-free (from electronic flash, flood lamps, flashlight, etc.) can be constructive in photographing fingerprints. Oblique lighting is used for most photographs of fingerprints. The well-nigh constructive manner to insure you are using the best angles of lighting is "preview the photo" by looking at lighting from several different angles. To do this, position a strong low-cal source, such as a flashlight, at unlike angles to detect the calorie-free angles that reveal the best detail in the fingerprint. Every bit you move the lighting you will encounter the results you will get by looking into your viewfinder. At this betoken yous can photograph the fingerprint using the lighting from the flashlight or you can position your electronic flash at the all-time angles for the photographs.
Whether using available light, electronic flash, or other illumination sources, bracketing of exposures should be considered. Bracketing may reveal more detail in "low contrast" or faint fingerprints. Underexposing the film will separate the steps on the white end of the gray calibration. Overexposure will dissever the steps on the blackness terminate of the gray calibration. The latitude for black–and–white film is generally two f–stops underexposure and 6 f–stops overexposure.
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Photographing Specific Types of Fingerprint Subjects
Dusted fingerprints with expert visible detail can normally be photographed without special lighting techniques.
Fingerprint impressions in soft substances (e.thou., wax, putty, clay, adhesive record, grease, or grit) crave the use of oblique lighting at a low angle. This volition create small shadows in the impression. Preview the event with a flashlight.
Fingerprints on porous surfaces (textured wall coverings, wood, brick, etc.) may demand almost a 90–degree lighting bending to avoid the creation of shadows in the surface'due south texture, which would interfere with the recording of fingerprint particular. Preview the effect with a flashlight. Fingerprints on glass (windows, drinking spectacles, etc.) can exist photographed by placing a white card behind the glass and using a depression oblique angle of light. They can too be photographed past using transmitted (back) lighting by positioning a diffused light source behind the glass.
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Bloodstain Photography
Bloodstain (too referred to equally blood spatter) at a crime scene tin tell the story of what occurred during an set on or other type of encarmine crime scene. Bloodstain analysis can determine such things as where victims and suspects were positioned when bloody blows occurred and events during the assault (e.g., which victim bled first). The crime scene photographer is responsible for photographically documenting a bloodstain scene in such particular that a bloodstain expert can later on do an analysis of the bloodstain testify. These photographs will include areas of bloodstain that indicate a pattern. An example of a pattern area is shown in the photograph beneath.
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When photographing bloodstain scenes use color flick to establish which substances in the photograph are bloodstains. Blackness–and–white film records reflected lite in shades of grayness, then when using black–and–white film it may exist difficult to determine what substances in the photography are actually claret stains.
Black–and–white motion-picture show may, however, exist used for high contrast photographs or with colored filters to increase contrast between the background and bloodstain. For example, if a bloodstain is located on a dark surface you can use blackness–and–white film and a reddish filter to lighten the bloodstain, or if a bloodstain is located on a low-cal surface you can utilise black–and–white picture and a blueish filter to darken the bloodstain.
When photographing bloodstains you must offset testify the location of the bloodstain with mid–range photographs followed with closer views to testify the bloodstain patterns. When taking close–upwards photographs of bloodstains be certain to identify a scale on the same airplane as the bloodstain. Self–agglutinative scales are convenient for photographing small areas, especially vertical surfaces, only a lightweight plastic scale can exist taped (using fingerprint record) to a vertical surface when necessary.
Position the photographic camera with the camera's moving-picture show aeroplane parallel to the bloodstain evidence. In club to get as much particular recorded on the motion-picture show as possible, your camera should be positioned so the frame of your viewfinder is filled with the bloodstain and scale. Using a tripod helps with the positioning of the photographic camera and steadies the camera.
This is important since depth–of–field is shallow in close–upwardly photographs. Precise focusing can be made with a photographic camera mounted on a tripod.
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Proper lighting volition show the detail of the bloodstain patterns and evidence. Practice not attempt to photograph bloodstain with an electronic wink positioned on the camera. If you do, you will unremarkably get reflection from the surface you lot are photographing. The reflection will obscure detail. The best style to lite bloodstain is with oblique lighting. Oblique lighting will reduce reflections and show greater detail in the prove. Use very low oblique lite angles when dealing with bloodstain on fabrics. The nigh constructive way to insure y'all are using the all-time angles of lighting is to "preview the photograph" by looking at lighting from several unlike angles. To practice this, position a potent light source, such as a flashlight, at different angles to find the light angles that reveal the best detail in the tool mark. As you move the lighting yous will meet the results you volition get by looking into your viewfinder. Position your electronic flash at the all-time angles for the photographs.
Some investigators will use strings to determine the origin of bloodstain at a offense scene. The origin is usually the location of a bloody accident in an assault. The technique involves measuring a group of blood drops on a surface, such as a wall, to find the bending that each drop of claret was traveling when it struck the surface. Strings are attached to the points each claret drop struck and the strings are then angled dorsum to an guess signal of origin. Photographs are then taken to document the demonstration.
Photographs can also be taken to illustrate theories involving bloodstain evidence, such as the position of a victim at the time of a bloody blow. In the illustrations beneath photographs are used to show the approximate location of the victim's caput at the fourth dimension of a encarmine blow. The first photo shows an area of the floor that has a void pattern. The void blueprint is an area without bloodstain. This pattern was acquired when a partition blocked bloodstain that traveled through the air from the point of origin. The second photograph was taken without moving the photographic camera, but with the electronic wink positioned where it was believed the victim's head was located when the bloody blow occurred. The second photograph shows a shadow, caused by the sectionalisation, that matches the void pattern.
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These ii photographs tin can be used in courtroom to assistance illustrate the testimony given by a bloodstain expert regarding the position of the victim's head at the time of the bloody accident.
Photographing Luminol
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Luminol is a presumptive test for claret ordinarily used to reveal bloodstain patterns on surfaces where the bloodstain has been cleaned or is not readily visible. Luminol reacts with the iron in hemoglobin causing the area with traces of blood to become luminescent. The luminescence is documented with photography. Other chemiluminescent chemicals, such as fluorescein, can be used in a similar mode.
When photographing luminol you will need a camera with "B" setting, a lens with a f/1.8 or larger aperture, a locking cable release, a tripod, an electronic flash, a curlicue of ISO 400 color print film, and a timer.
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To photograph the results of luminol within a building you lot would offset plough off lights in the expanse and spray a fine mist of a luminol solution over the area to be searched. If luminescence is observed, notation its location. Adjacent, turn on the room lights. Set up a camera, equipped with a locking cable release and an electronic flash, on a tripod. Accept a normal photograph of the area. Without moving the photographic camera, advance the film and adjust the lens aperture to underexpose the next photograph by ii f–stops. This tin exist done with an automatic camera by adjusting the exposure control setting (to a setting of –two) or with a transmission camera by endmost down the lens aperture (due east.g. if the normal flash photograph requires a f/v.vi, alter the aperture to f/eleven). Set up the shutter speed to "B." With the room darkened, open the shutter (firing the electronic flash) and lock the cable release to hold open the shutter. Open the lens aperture all the fashion while taking intendance not to move the camera. Lightly spray luminol on the area in the view of the camera. You will need to spray the area every twenty seconds to maintain luminescence. Avoid over spraying, which may crusade patterns on smooth surfaces to run or may cause background luminescence and reduce needed dissimilarity. Close the shutter after well-nigh one minute.
A scale tin be used in the luminol photograph. Attach small pieces of copper wire on the one inch–marks of a scale and place the calibration in the area to be photographed. The copper wire on the calibration will go luminescent when sprayed with Luminol.
Bullet Path Photography
The suspected path of a bullet can be illustrated with a variety of techniques. Colored strings can be strung to illustrate bullet paths. Reflective string can besides be used—the cord volition glow when a flash photograph is taken. Fiberglass rods or wooden dowels can besides exist used, particularly to show how a bullet passed through an object or wall. With these techniques you volition need to set up the strings or rods and photograph the area from several angles to document the bullet paths.
Another technique for photographing the suspected path of a bullet is to use a laser beam. As with the other techniques, the bullet paths illustrated with laser beams are documented with photographs.
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When photographing a bullet path illustrated with a laser you will need a camera with "B" setting, a lens with f/ane.viii or larger aperture, a locking cable release, a tripod, an electronic flash, a roll of ISO 400 color print film, and laser.
To photograph a bullet path using a laser you first position the laser to illustrate the suspected bullet path. Then set up a camera, equipped with a locking cable release and an electronic wink, on a tripod. Adjust the lens aperture to underexpose the photograph by i or ii f–stops. This tin can be done with an automatic camera past adjusting the exposure control setting (to a setting of –1 or –2) or with a manual camera by closing down the lens aperture (e.g. if the normal flash photo requires a f/5.vi, alter the aperture to f/8 or f/11). Gear up the shutter speed to "B." Plough on the laser. With the room darkened, open the shutter (firing the electronic flash) and lock the cable release to agree open up the shutter. Open the lens aperture all the mode while taking care not to move the camera. Cause the laser beam path to show in the photograph by either spraying photographic fog in the path of the laser beam, or by slowly moving a white card along the light amplification by stimulated emission of radiation beam path with the menu positioned and so the laser dot on the carte du jour reflects toward the camera. When you cease tracing the light amplification by stimulated emission of radiation beam path return to the camera and shut the shutter.
Summary
This chapter has given you a multifariousness of techniques for photographing some of the more common types of evidence found at crime scenes. However, crime scene conditions and types of evidence vary profoundly from ane criminal offense scene to the next. To successfully photograph evidence you lot must exist experienced and knowledgeable in both photography and forensics, exist willing to experiment with lighting, be a problem solver, and be artistic.
Show Photography — At the Crime Scene Copyright: © 2014 by Steven Staggs. Copyright for this article is retained by the author, with publication rights granted to the Crime Scene Investigation Network. This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License which permits unrestricted noncommercial utilise, distribution, and reproduction, provided the original work is properly cited and not changed in any way. Based on a work at http://world wide web.staggspublishing.com/CrimeScenePhotography.html.
About the Volume
The data presented in this article is from the book
Criminal offence Scene and Evidence Photography, 2nd Edition © 2014 by Steven Staggs.
Crime Scene and Evidence Photography, 2nd Edition is designed for those responsible for photography at the criminal offence scene and in the laboratory. Information technology may be used by constabulary enforcement officers, investigators, crime scene technicians, and forensic scientists. Information technology contains instructions for photographing a variety of crime scenes and various types of evidence. Information technology is a valuable reference tool when combined with training and experience. Crime Scene and Bear witness Photography is also a helpful resources for students and others interested in entering into the field of crime scene investigation.
Criminal offense Scene and Evidence Photography, 2nd Ed may be purchased from the publisher.
Also bachelor in a downloadable PDF version for but $24.95!
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About the Author
For the past thirty years Steven Staggs has been a forensic photography instructor and has trained more than than four,000 crime scene technicians and investigators for police and sheriff departments, district attorney offices, and federal agencies. He is besides a invitee speaker for investigator associations, appears as a crime scene investigation expert on Discovery Aqueduct's Unsolved History, and provides consulting to law enforcement agencies.
Steve has all-encompassing feel in crime scene photography and identification. He has testified in superior court concerning his crime scene, evidence, and dissection photography and has handled high contour cases including a nationally publicized serial homicide example.
Steve is the author of the Criminal offence Scene and Prove Photographer's Guide, a field handbook for crime scene and prove photography, which has sold over 40,000 copies and is in use by investigators in more 2,500 law enforcement agencies.
Steve retired in 2004 afterward 32 years in police enforcement, just continues to teach forensic photography and law-breaking scene investigations at a university in Southern California. He is the President of Criminal offense Scene Resource, Inc. and Webmaster of the Crime Scene Investigator Network, the world's most pop Criminal offense Scene Investigation and Forensic Scientific discipline website (world wide web.crime-scene-investigator.cyberspace).
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Article posted: September 22, 2104
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