Crime Scene Photography - Footwear Marks

by sc_shivatsal (student)

PHOTOGRAPHY OF FOOTWEAR MARKS

Crime scene photography is concentrated on taking correct pictures of crime scenes and criminal proof, so these pictures is employed in a criminal investigation, and within the potential prosecution for criminal activities. Individuals are taking pictures of crime scenes ever since the primary camera was fictitious as a result of it absolutely was realized that also pictures may be a useful gizmo within the method of a criminal investigation. Modern photography of a criminal offense scene is meant to supply an in depth, correct and truthful image of the scene and to accurately document each the crime scene itself and therefore the succeeding criminal investigation. Crime scene photographers are the primary individuals allowed into a scene of crime, this can be to do and maintain the crime scene and supply as truthful image as doable.

Crime scene photographers start by taking overall scene shots & then move in to smaller areas & then take specific shots of potentially important facts such as footwear marks. The images taken by a crime scene photographer must contain facts markers & scales, & rulers when necessary to retain relevance to the inquiry. Police officers may use images from crime scene photography to be able to reconstruct a crime scene. The photographs may even be used in interrogation & in courtrooms to provide both the judge & the jury with facts of what the scene looked like & of important features of a crime scene, for example a knife. It is & a lot simpler & safer to show the knife, which could be a murder weapon, as an picture to the courtroom along with the correct documentation in which the facts pathway & handling of the facts document, than bringing the actual evidence package in to the courtroom.

Digital cameras have massively expanded the field of photography in a criminal investigation; this is because they allow photographers to shoot images extensively, allowing them to capture every possible detail on a small media card rather than rolls and rolls of film. However this could also provide problems because it could lead to a photographer or even an investigator flicking through hundreds, or thousands of images of a single crime scene.

Although this method provides better probability that a potentially important image may not be missed because of a crime scene photographer being conservative with the camera and amount of film used. When entering a crime scene the photographer will take images from a long range that show the overall crime scene, mid-range photographs will be taken that show a closer view of a certain area; and close range photographs will concentrate on a particular area or object such as a footwear mark or impression. Crime scene photography is a non-destructive method of recovery of a footwear mark. Photography of a footwear mark should always be the first method of recovery by a crime scene investigator before any other recovery methods are used.

Most close range photographs will be captured at less than actual size; this will mean a rigid scale will need to be included. When enlargements are made to a picture to examine sure aspects of that picture, they can be enlarged to a natural size only by referring to that scale. This means that the enlargement is sized so that for example 1mm on the scale in the enlarged photograph equals actual millimetre.

A camera which would produce a picture which is the natural size picture (a one: 1 photograph) is not practical to be present at a crime scene, the use of a practical scale in the photograph is absolutely essential so the photograph can be exactly enlarged. The scale used ought to ideally extend the full length of the impression, it ought to be positioned evenly & on the same plane as the impressed surface, and this is more difficult with a short scale. The length of the scale is important when making natural sized prints of the picture for accuracy purposes. The scale ought to be level & parallel to the footwear impression, this is because if the scale is not level & parallel, it may cause point of view & scaling issues. Images taken of impressions from directly above the impression & taken in the correct manner won't provide significant point of view issues. Something present in the picture will provide viewers of an picture, such as the judge or the jury, confirmation that the point of view is correct.

Whereas pronounced perspective problems are usually very clear in a photographed impression, minor perspective problems are harder to identify without aids. In the case of a ruler, certain aids can provide support in detecting and potentially correcting perspective problems. A right-angled ruler is a better instrument to determine and correct any perspective problems than a straight ruler. Right angled rulers are also very helpful when a photographer is forced to take an image of a footwear impression from an angle as it is easier to correct any perspective problems. When using a right angled ruler it is important that the ...

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Figure 1 the depth of field is found on most lenses between the aperture F-stop ring and the distance rings.

When photographing three dimensional footwear impressions, it is essential that the depth of the impression is measured in its entirety. To do this several photographs have to be taken with the scale positioned at numerous different depths. The numerous photos taken are to be taken from the same position with the scale square to the lens at all times and it moves further and further away from the lens to show the different depths of the impression. In an image of a footwear impression several things should be included in the image for it to be helpful to an investigation and to provide as much information as possible. These items include an identification label, an orientation arrow, and an angle setter. The identification label must always be included and the label should tell the image viewer the location of offence, location of the footwear mark, the date, the crime scene investigator’s name and the exhibit number. This is important because at a crime scene there may be several footwear impressions maybe at different locations throughout the crime scene, having the identification label in each image enables each image to be linked to other details such as scene sketches, notes, logs as well as lifts and casts. The orientation arrow should be placed at intervals the photographic image. This allows the orientation of the footwear mark to be determined at intervals the scene. The angle setter may be a level that determines the angle at that footwear mark lays at intervals a criminal offense scene. the utilization of the angle setter can facilitate the artist make sure that the proper procedures are adhered to concerning the capture plane, scale, label and footwear mark square measure on an equivalent plane.
The rack is a vital issue once photographing footwear marks. the perfect position for a footwear impression image is directly higher than the impression. The rack helps with the right positioning of the camera as a rack will hold the camera directly below its’ centre and provides a gradual base that helps hold focus and prevent movements of the camera moving the image. so as to avoid a perspective downside it's vital that the camera is parallel to the footwear mark, and therefore the rack is ready to supply this notwithstanding the footwear mark is on Associate in Nursing angle which might be shown on the angle setter. Once using a rack it allows the camera timer to be used additionally to minimise movement of the camera, by reducing the movement place upon the camera once the capture button is ironed, which can additionally cause a loss of focus or a perspective downside. The rack additionally allows the artist to possess his hands free for alternative tasks like managing the sunshine supply and exposure. A rack additionally makes it easier once photographing multiple footwear marks or impressions because it makes it easier to makeover from one place to a different at intervals criminal offense scene. To confirm everything is correct with a picture before the matters of exposure and lighting square measure proscribed the artist will use a cameras’ finder to confirm that angles, image size and focus square measure all correct before trying to line the lighting and exposure.

When photographing three dimensional footwear impressions a cameras opening should accommodate the depth of the footwear mark. The NPIA recommend an opening setting of between F16 & F22. For two dimensional footwear marks the NPIA recommend an opening setting of around F8 to F11.

Figure 2 incident light

There are many different types of lighting that could be used by a photographer at a crime scene. When photographing footwear marks and impressions. Some marks and impressions can be taken using natural light, or sometimes natural light has to be restricted; however more often than not artificial lighting will have to be used. The purpose of lighting is to achieve a contrast between a footwear mark and the soil or other surface the mark or impression lies in or upon. If natural light is not good enough to provide the image with enough contrast there are many artificial light sources that could be used by the photographer such as, reflectors, crime lights, slide projector, oblique LED's or fibre-optics, polarised light, or sometimes a camera flash can provide the needed contrast in the image. However when using a camera flash the flash should never be mounted on the camera, this is because a flash mounted on the camera causes a reflection of light back into the lens, known as "flash-bounce"2 and this flash bounce causes a section of the photograph to become over-exposed and will be of no use in the investigation.

Figure 3 this image shows a footwear mark with over exposed areas, these over exposed can be seen around the top end of the heel area of the shoes

This image shows the footwear impression in the soil, but there are no lighting sources to produce distinction and detail among the footwear impression. Oblique lighting allows most detail to be captured by the creative person by providing distinction. To obtain this a lightweight source has got to be placed at a low angle of incidence relative to the surface the footwear impression is in. This low angle creates shadowing among the footwear marks higher and lower areas and this provides the inflated quantity of distinction among the image. For this impression in the soil, the angle of incidence to place the oblique lighting source depends on the depth of the footwear impression. The bigger depth of the impression, the bigger the angle of incidence will be, so if a footwear mark is deep the oblique source of illumination will be higher from the bottom. When victimisation oblique lighting several images got to be taken of the footwear impression and for each image the oblique source of illumination has got to be repositioned. The idea of oblique lighting is to improve the distinction among an image by creating shadows on the low areas while illuminating the higher areas.

When photographing the footwear mark as a creative person they test completely different light-weight sources to find the best possible image, though the creative person always has got to have the inverse square law3 in mind.

Figure 4 The inverse square law

The inverses square Law states that associate degree object doubly the space from a source of light will receive a quarter of the illumination. In terms of footwear marks basically it means that if the oblique lighting source is positioned on the length of the footwear from the toe end of the footwear mark, the toe end may be over exposed and therefore the heel end under exposed. A way referred to as fill lighting4 can counteract the under exposure. This uses a reflective surface placed at the other end of the footprint to the oblique lighting source, this reflects a number of the oblique lighting back into the footwear mark to do to create more distinction and therefore more detail among the image. From a photographer’s perspective the inverse square law means that if you double the space of the footwear mark from the light source, you'll need fourfold the number of sunshine for constant exposure. Perspective problems occur when the camera is not parallel to the footwear mark or impression that is being photographed. To avoid this problem a stand should be used and the image mustn't be taken by hand. Though in three-dimensional footwear impressions, sometimes although the camera is parallel to the impression perspective errors can occur usually in deep impressions. This happens because in manufacturing the image, the impression is converted from a three dimensional impression to a two dimensional image of the impression.

Figure 5 The colour wheel shows the three primary colours

Colour filters work by selective absorption or transmission of the sunshine reflected from the mark or its surface. A filter can transmit its own colour and absorb or block its opposite colour. The filter has an impression on the ultimate monochrome print therein its own color are going to be lighter shade and its opposite colour are going to be darker shade. This impact is also any increased when photographing during a darkened space, employing a coloured source of illumination is used in conjunction with a filter. this could be of nice use once photographing footwear marks on a colured background. A set of six colour filters is needed to lighten or darken any colour. The six filters comprise of 3 primary colours; RED, inexperienced and BLUE and three secondary filters; CYAN, MAGENTA and YELLOW. Colour filters area unit used with black and white panchromatic film; with some digital capture systems it's attainable to convert colour pictures to monochrome among the camera. It higher but to shoot in colour mode, use the suitable filter for black and white film and have the photographic workplace convert the image to greyscale post capture. The image viewed on the monitor can look strange however the improved impact are going to be similar to victimisation black and white film. The use of colored lightweight can have an analogous impact to the utilization of a colour filter therein it'll lighten its own colour and darken its opposite colour. The CSI ought to experiment victimisation filters and colored lightweight sources to optimise the distinction inside the captured footwear mark image.

Figure 6 tripods at crime scene footwear mark in soil

The National Policing Improvement Agency (NPIA) provides a 14 point guideline for taking a footwear image.

Handhold the camera to determine the tripod position, image size and access.
Place grey ridged ‘L’ scale alongside footwear mark so it conforms to length and width.
Ensure ‘L’ scale is on the same plane as the footwear mark.
For three dimensional footwear marks a series of photographs will need to be taken with the ‘L’ scale at the various depths and angles, which represent all the depths and angles of the footwear mark.
Include directional arrows on the label.
Install the tripod and camera – ensure everything is stable.
Align the camera, footwear mark and scale accurately using the angle setter.
Set the camera so the footwear image is as large as possible in the view finder and within the printing parameters.
Set the camera so the footwear image is as large as possible in the view finder and within the printing parameters.
Select appropriate lighting or shading.
For two dimensional footwear marks consider the use of reflectors to obtain a more even distribution of light across the footwear mark.
Consider restricting any ambient light (natural or artificial) falling onto the footwear mark area in order to achieve the best effect of oblique light.
Work out exposure time to suit aperture and lighting selected.
Take several photographs, change position of the source of light to ensure that all areas of the footwear mark are correctly exposed.”

Figure 7 this is image of the footwear impression in soil.

In conclusion it's been proven that good quality pictures have many uses in the field of forensic science and the investigation of a crime. They’ll help SOCO/CSI/FS/FI and also the police, do a crime scene reconstruction (Gardner & Bevel, 2009), wherever the sequence of events leading up to, throughout and instantly once the crime is realised. Sometimes photographs area unit used as aids for witnesses, to recall more concerning what they saw (Kiley, 2006). pictures is faxed, announce and emailed between police forces and widely distributed within the media or throughout a neighbourhood in the search for a missing person, suspects for further items of evidence(Red sicker, 2001). Later within the criminal justice method judges and jury members are also conferred with photographs throughout a trial to assist they perceive the character of a crime (Kiley, 2006). Typicallypictures of an item of proof are going to be wont to stand in for the real factor if the item couldn't be far from the scene of crime for some reason, or if it's not possible to urge it into the court area. Photographic techniques area unit advancing all the time and it's the task of the rhetorical photographer to make best use of these to create strong, detailed images of all the proof pertaining to a selected crime

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