Presentation on theme: "Forensic Aspects of Photography"— Presentation transcript:
1Forensic Aspects of Photography Although forensic photography is simply the application of photographic principles to forensic situations, proper archiving includes rules that are inviolate.
2Invariant Rules of Forensic Photography The first photograph in a series must have an incident photographic worksheet or cover sheetPhotographs must be listed in a photo logCamera settings – date – case number – initials – evidence numbers.Types of Forensic Photographs:Establishing, midrange and close-up photographs
3Invariant Rules of Forensic Photography Illumination (metering) should be appropriate to capture impression evidence detail.TripodsTripods should be used for all photographs where the camera must be steady: close-ups, certain mid-range photos, Luminol (BlueStarTM) photography and dim light situations.The camera (and tripod) should be perpendicular to the plane in which the evidence lies and horizontal (parallel).Photographs should be taken before and after each on-scene manipulation (enhancement attempts) of evidence.The pop-up flash on the camera should never be used except in specific circumstances.
4Scene Incident Photographic Worksheet The scene incident photographic worksheet is the cover for a book or series of photographs.Not the same as the photographic logThe cover sheet for a set of scene photographs that are listed in a photographic log.The Photographic worksheet has specific data that includes the date, time, agency, case number and the name of the photographer.Has color stripes for determining whether the camera is “seeing” colors correctly.Can have scales for estimating sizePhoto ID CardsproductName= &CategoryName=Crime-Scene-Documentation-Photo-ID-Cards
5Photo Log List of all the photographs taken in a specific series. Each entry contains the specific photographic and forensic information needed about that specific photograph:Camera settings, description of what the photograph was and the type of photograph – establishing, midrange, close-up.Can have other case-specific information.
6Critical Forensic Photographs Forensic investigations require complete coverage.Archiving is critical to that processArchiving must cover the entire crime scene as though making a documentary.Means capturing landscape and close-up photosForensic Archivist must be an expert in recognizing evidence at the crime sceneAND capturing it in the three principle photographic types: establishing, midrange and close-up.
7Critical Forensic Photographs Category of PhotographReason for the PhotographEstablishing(Overview)Continuous, overlapping perspective of the scene.No scales are necessary.Maximum depth of field (f/11-22).Depict the general orientation of the sceneEstablish the relative position of evidenceMidrangeCapture the immediate surroundings and relative relationship of items of potentially probative evidence.Scales may be necessary depending on subject. If so, photographs should be with and without scales.Maximum depth of field (f/8-16).Close-up(Macro Photographs)Capture detail of potentially probative evidence. Photographs with and without scales.Shallow depth of field (f/1.4-4).
8Perspective in Midrange Photographs After the establishing photos, the next step is to “get closer” to the evidence photographically so that its relative position in a specific area of the scene is made clear.Establishing shot shows knife lying some distance from the deceased’s outstretched right arm.Midrange shots pinpoint knife’s position perfectly, which could require more than a single photograph encompassing multiple perspectiveFrom the deceased’s feet, from the outstretched right arm, looking from the knife to the outstretched arm, from the left and right sides of the deceased, from the deceased’s head, from all doorways if they not too far away … etc.Knife’s position relative to the doorway, the deceased and other rooms is preserved - archived.
9Midrange PhotographsA single bloodstain pattern at a scene should not present an archiving problem, but multiple bloodstain patterns should be labeled sequentially … specific designation different from other tagged evidence.If most of the evidence at the scene is tagged as, say, items 1-99, the bloodstain patterns could be tagged using alphabet markers, such as A-Z.Scales should be present in all bloodstain pattern photographs. Flash should never be used for bloodstain patterns. Gardner, Ross A. ibid, page 147. Attribution to Toby Wolson
10Close-up PhotographsAll Evidence having detailed investigative value –Knife length and width - must be preserved photographically.Pattern evidence: Fingerprints, footwear impressions, tire tracks, tool marks, etc.1st photograph taken without scales …2nd second with scales.The scales must also be appropriate:A fingerprint requires millimeter scalesknife on the floor does not require that much detail and can be photographed using an inch ruler.
11Rule of Thumb for Close-up photography? Close-up PhotographsUse tripod because any movement blurs or obliterates critical evidentiary detail.Rule of Thumb for Close-up photography?The rule of thumb:Any evidence that will not be removed from the scene that has direct comparative valueAny evidence that has potential comparative valueDoF: Close-up photographs are absent DoFPhotographer opens the aperture and concentrates on focusFill LCD viewfinder with the image of the evidence.
15IlluminationThe relative position and type of light entering the camera.Location of the light source.The type of light refers to a flashlight or IR, UV, or light from an ALS.Alternate light sources (ALS) are indispensible tools for highlighting important items of evidence.Varying wavelengths of light can visualize small items of evidence (microscene elements).
16Light Interacting With Matter Object FluorescesLightSource(White - ALS, UV, IR)ObjectLightAbsorbedReflectedTransmittedReflected LightEyeOrFluorescenceReflected LightCameraBarrier FilterBarrier Filter Blocks Reflected LightBarrier filters are different colors depending on wavelength of light
17Reflected Light can Mask the fluorescence. Barrier filters.Block reflected light so it never gets it to observer (camera and/or person).The orange goggles used in CSI are barrier filters that block the reflected lightWhen blocked, fluorescent light enters the camera and is “seen” by the digital sensor and the photographer,Goggles of an appropriate color are necessaryOrangeRedClearYellow
18Crime Scene Photo Archiving Review Using tripodsClose-upsDifficult shots outside – when long exposures are necessaryShots with scalesMidrangeFast shutter speeds (< 125th or 60th with fast lens)Low light requiring long exposures – avoid high ISO valuesLuminolFluorescent photographyEstablishing Shots:Maximum Depth of FieldSmall aperture (large f/number)Slow shutter speedCreates possibility of vibration movementClose up Shots:Shallow Depth of Field18
27Photographing Common Scenes All crime scene investigations follow a roadmap or menu of activities.Challenge: Follow precise schedule without undermining the intellectual thought process.Establishing photography is one of the first activitiesMust be done logically and fit team leader’s investigative philosophy.Photography is one part of the investigative puzzle.Not an independent activityMust fit the logic of the investigationCannot interfere with the processing flow.
28Photographing Common Scenes Use logic concerning where archiving begins AND its sequence.Generally, photography begins where activity took place.Where team begins investigative efforts.Where the photographer and team spends most timeMakes scheduling difficult but critical.If photography happens out of phase, investigation will be inefficient … may miss critical evidence. .
29Photographing Bodies Photographing the body is important, Done properly proper time.Dictated by how the investigation moves forward and the involvement of the medical examiner.Body is part of the macroscene and is scene unto itself.Has critical evidence that can help close the investigation or provide critical probative evidence.Blindly photographing body 1st is illogical AND not necessarily correct.Not necessarily a major source of fragile evidence that requires immediate attentionDoes not need to be removed from the scene immediately.Might not be where most of scene activity took place.
30With Respect to Archiving Defining Scene types,With Respect to ArchivingCertain scene types require specific considerations.The crime types include: vehicular accidents, homicides, sexual assaults, burglaries, hit-and-run, suicide, arson and bombings.Each scene dictates the specific and necessary archiving details.
31II: Ancillary Archiving at Homicide ScenesI: Body & SurroundingsReason for PhotographEstablishing overhead view.To capture the surrounding area from an aerial view. The shot should be as vertical as possibleMid-range photographs of body taken clockwise – head-to-feet, right arm and side, feet-to-head, left arm and side. A tripod may not be necessary. But if the area is dark, a tripod may be necessary.Gives the perspective of the body’s surroundings.Close-up views using a tripod– head, hands, feet, clothing, wounds, bite marks, etcDocuments the detail of the bodyWeapon-specific photographsThis is to capture bullet holes in furniture, walls or other defects – knife marks, etc.Mark the position of the body with markers. It is not necessary to outline the entire body with chalk, just location of head, hands and feet.Knowing the precise location of the body helps if investigators must return to the scene. With photographs in hand and marks of head, hands and feet will suffice to show investigators the relationship of the body to the scene.ALS photography of the bodyThe body should be photographed using an ALS in order visualize biological evidence (semen, saliva etc) and fibers. It is important to do it at the scene so that the relative location of the evidence can be seen in relation to the position of the body.II: Ancillary Archiving atHomicide ScenesEstablishing photographs of the scene exterior, , e.g., from feet. 1st shots of front of house and driveway - move clockwise.Depending on weather conditions, last photographs taken. Include landscaping and impression evidence. Aerial photographs - on-line services may be able to provide these. Photograph looking away from the scene.Establishes exterior boundaries. Could be helpful in establishing egress and /or entry routes, possibly in retrospect.A perspective of the area surrounding the scene from the scene’s viewpoint can be important.All rooms that have activityAreas where evidence is likely located. Capturing this information critical.Areas that do not have activityNo one knows when other, visually non-active areas of the indoor scene may shed important evidence.Establishing, mid-range and close-ups of areas where fingerprints are found or where it is suspected they might beThis will help provide a visual perspective of the perpetrator(s) movement through the scene.Indoors and outdoors, impression evidence must be photographed and, it possible, lifted or cast.Impression evidence can be compared by forensic scientists with samples taken from suspects.
32Reason for the Photograph Sexual Assault CasesSexual AssaultReason for the PhotographUsual scene photography including entrance and egress points.Interior and exterior establishing shots as in homicide investigations above.Establishing photography is SOPEntrance and egress points important - location can support or refute victim’s/suspect’s allegation.ALS Photography of the sceneLocate biological & fiber evidence.Location is important to verify & support victim’s/suspect’s statements.
33Arson Cases The Burning Fire Scene Reason for Photograph Establishing exterior shots of the fireExternal meter necessary for digital photography,RAW files criticalPhotograph all sides of the burning building WHILE burning if possibleExternal meter captures correct incident light.RAW files obtain the proper WB impossible with JPEG files.Fires flow upward and outward from a source in a 3D pattern.Establishing shots capture movement.Establishing shots capture fire flow changing direction when new fuel source encountered or if fire reaches obstruction.May capture flashover –fire not suppressed in a confined space can reach 1100oF & ignitable items burn.Items below hot gas layer & not in direct contact with flame will ignite & help propagate the fire.Capture color of flames – can indicate type of material burning but NOT temperature of the flame.Individuals in the crowd or standing alone watching the fire.
34Arson Scenes After the Fire is Out Reason for Photograph Establishing exterior shotsIdentify fire-flow patterns to correlate with those taken while the fire was burning. Elevated views help locate roof involvement.Difficult: Damage related to fire fighting efforts may obliterate traces of the perpetrator(s). Identify entrance/egress points of possible arsonists. Discarded items used to start the fire, tire tracks of non-official vehicles, etc:Establishing interior shots of the fire. External meter is necessary.Purpose is same for any scene: to capture fire and fire suppression activities. Indicates possible location of fire patterns and preserves damage and position of bodies or missing items.Mid-range interior shotsDocument char, smoke and soot patterns to understand development of the fire flow. Damage patterns on furniture: charring, soot, melting and the location of vertical and low-burn patterns.Document immediate surroundings of evidence of a criminal nature, such as bodies and accelerant patterns pointed out by the fire marshal.Close-up interior shotsDocument fire patterns or signs indicating natural, accidental or deliberately set fire.
35Photographing Dark Areas Attached Flash Unit(s) On-Camera FlashAttached Flash Unit(s)Painting with LightSlaves