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Spring, Gale --- "Photography as an evidentiary tool: the creation of accurate evidence" [2001] AltLawJl 102; (2001) 26(6) Alternative Law Journal 281

Photography as an evidentiary tool: The creation of accurate evidence

Gale E. Spring[*]

Standards need to be developed for forensic photography at a State, national and international level.

Since its birth in 1836, the question of whether photography is an art or a science has been debated. In truth, it has a foot in both camps leaving the contemporary viewer to continue the debate. Although the art cannot be excised from the practice of photography, proper photographic technique for evidence documentation always strives to reproduce a fair and accurate representation of objects or scenes, without bias or judgement. There is a lot of science and mathematics involved in reproducing three-dimensional space on a two-dimensional piece of paper and then interpreting it back to relationships of position and size as well as disclosing other measurements and details that may be required.

Frozen memories

Photography records a moment in time. Nothing is more crucial than time when trying to solve a crime. Evidence must be inspected on-site, then removed from the scene and analysed, leaving the photographic image as the most accurate and permanent record of the event as it was seen.

Photographic documentation becomes even more crucial if the evidence is transient. Transient evidence only exists for a short period of time. Bite marks, rope bindings that will be cut or untied, the state and position of a victim at the scene of a crime, will be altered or deteriorate soon after the investigation. Figure 1 shows one photograph in a series taken to record how a knot was tied. A similar knot may show up in a future homicide.

It is most important that transient evidence be recorded in a precise manner so photographs of the same or similar objects may be accurately compared with photographs that may have been taken weeks, months or years apart. Even objects that do not change and are held in a police evidence room may be discarded after some defined period of time. The only remaining records may be photographs.

Figure 2 shows a police photograph of a device used to make bricks of heroin. The device was confiscated by the police. Months later the device was shown to the defence who questioned whether it had been modified or was even the same object. Comparison photographs were made from a similar angle and lighting to the police photograph. It shows there had been some unexplained markings on the central post.

The truth, the whole truth …

Photographs as evidence are extremely powerful when shown in court. People tend to believe what they ‘see’. The danger is that they may ‘see’ what they are told the photograph shows or may be misled by poor photographic technique. The photograph should be a true representation of reality since others may need to draw conclusions from the photograph without the assistance of the photographer.

What’s the question?

Any photograph may be considered evidence. It depends what questions you expect the photograph to answer. When faced with a photograph that ‘shows’ something of interest, most viewers believe everything in the photograph represents truth — or at least an accurate representation of reality. This may not be the case. We may all agree that an out-of-focus photograph show two vehicles collided at an intersection, but may not agree on the make, model, colour or vehicle identification number. We may agree that a surveillance video shows a suspect with a tattoo, but not agree on the exact detail of the design. We may agree that a technically perfect photograph depicts a man in a boat near the mouth of a river, but without some precise technical information, we may not be able to determine how far he is from shore. Photographs admitted into evidence are potentially dangerous if the questions are not clearly defined and properly interpreted with respect to the specific questions the court wants to clarify. Many times the key is hidden in technical information that was not documented. The photograph becomes worthless for answering those questions.

Need more information?

As mentioned, the significance of some evidence may not be known when first witnessed by the investigating officer, the police photographer or the forensic pathologist. Many times the photographs of the scene must be viewed again in light of the importance of new evidence or new questions. It is crucial that the original photographs be of the highest quality in the event extreme enlargements must be made to reveal additional detail or information. Areas of interest are not always in properly lit and properly exposed areas of the original photograph. Here, the photographic expert may be asked to extract information and detail from poorer quality regions of the original negative or transparency. Unlike Hollywood techniques or popular television shows, this is not always possible.

In the case of serial killers or other repeat criminals, crime scene investigators or photographers may not see similarities of evidence at first. Pieces of evidence may re-appear or a modus operandi may be discovered through the comparison of photographs taken at the crime scenes or at autopsy. At first, general photographs of the scene may not have targeted these as important; however, they may become key clues tying numerous cases together. Since some of this evidence may have been transient or even discarded, similarities with other crime scene photographs may be important evidence to demonstrate to the court. If the photographer has competently covered the scene, earlier photographs may be enlarged to detail this evidence. As soon as the pattern is discovered, good standardised photographs should be made for comparison.

Investigators take and rely on their notes from the scene to assist their testimony in court. Even if photographs are not used as evidence, they play an important role in assisting the investigator to recollect the events in detail, share the experience with others and possibly reveal additional information that may not have been seen as important at the time.

The proper documentation of evidence is one of the most costly exercises that may be done in the investigation. If the photographic evidence is done to a high standard of precision, they can support the case and help win a conviction. If done poorly, they can confuse the court to the point of losing the case. Most people expect that photographers responsible for such important duties would have the depth of knowledge and experience in their specialist area just as fingerprints or DNA experts have in theirs. This is sadly not the case. Photography is not seen as a specialist investigation discipline. Proper training and education is seen as expensive and possibly unnecessary. Forensic and crime scene photography has been a victim of the philosophy of multi-skilling for some time. It has no real external benchmarking and suffers from being seen as something most anyone can be trained to do.

Taking or creating photographs

Most people refer to the act of photography as ‘taking’ a picture. This implies the photograph is some real and tangible thing that one reaches out and possesses. The fact is all photographs are created through mechanical, chemical and electronic means. The photographer creates the photograph at the scene. The photographer selects the exact moment in time, angle of view as well as editing what is deemed important enough to be photographed. The photographer, the viewer and the court should never forget that the photograph is only a representation of reality. It is a creation by the photographer. It may need to be further interpreted by the photographer or another expert.

We are bombarded daily with photographs used for commercial and advertising purposes to make things look bigger, better and more alluring. They want to convince the viewer to buy their product. But photographs may also be used to accurately document and subsequently re-construct a scene or event at a later date. Evidence documentation leaves no room to ‘sell’ its message. Its accuracy must have some basis in science. If done properly, the photograph needs little or no explanation. It can tell the complete story.

For the record

For many years, medical photographers have established protocols and procedures to produce standardised medical photographs. This ensures medical conditions are accurately recorded for further study by the physician and colleagues at any time in the future. Many books on medical photography have been published over the years and have established professionalism in this type of specialist photography. In the area of medical science it was recognised that a standardised practice had to be established because physicians were comparing their images and data with others around the world. They were also looking at changes over time through serial photographs. There are local area variations due to specific needs, but all have their foundation tied to an international standard. Figure 3 shows the same person photographed from three different camera-to-subject distances. The head size (magnification) remains the same by using three different focal length lenses. Notice how the shape of the face changes. Without a technical explanation, the viewer could believe it may not be the same person, or the photographs were taken at different times or the subject may have a pre and post medical condition.

The consistency and accuracy of medical documentation must continue over time and by each successive photographer if meaningful comparisons are to be made at a later date. The historical significance of some medical images may not yet be immediately recognised but prove useful decades later. If the standardisation of medical photographs is maintained over that time, the photographs may prove more important for extracting data.

Training, education and taking pictures

There are trained photographers, educated photographers and those who simply take pictures. The difference may be crucial to images that must depict a fair and accurate representation of evidence. It is also important if additional techniques such as photogrammetry are needed. Photogrammetry is the science of extracting measurements from photographs.

Everyone is a photographer. This idea has been sold to the public since the early days of photography when Kodak advertised in 1889: ‘You press the button, we do the rest’. Many camera systems are sold today on the basis of ‘point and shoot’. It is true — all of us can take photographs. Understanding and interpreting what we have just created is another story.

Training refers to the understanding and execution of procedures and protocol in capturing images. Guidelines or instructions may be set up so anyone can create these photographs to a workable standard. This documentary approach of creating photographs is acceptable under many circumstances. If the procedures and protocols are set out well, additional information can be extracted if necessary. An example of this is surveillance cameras. Anyone can change film and maintain the camera to a basic level, but the only a professional can set up the camera for the best lighting and angle as well as establishing the proper focal length lens and plane of focus so exact measurements of a suspect’s height may be determined. The ‘shop-owner’ installation is usually inadequate to give any usable information.

Education refers to the depth of understanding of what may affect the outcome and subsequent interpretation of the image such as the type of film stock selected, quality and type of lighting, and the choice of lens and distance of camera to subject. It also includes a few technical issues such as depth-of-field and shutter speed as well as techniques such as photomacrography and ‘painting with light’. The professional forensic and law enforcement photographer must be able to determine on-site, what information is or will possibly be needed so decisions can be made on the technical approach of documenting the object, scene or event. These deeper questions may be extremely important to the final interpretation of information captured on the film. These questions may not be asked for years; therefore, along with the photographs there should be notes and guidelines to support the photographs. A photographer who has a foundation in technical imaging and scientific principles can make proper decisions when creating the photograph.

Having made the case for well trained and educated forensic and law enforcement photographers, it is worth mentioning that even a ‘snap shot’ may be used to record objects or events. In may instances, questions regarding the camera, film, lighting and photographer’s position can still be answered and equipment obtained so additional information may be accurately understood.

And in conclusion…

Standards in medical photography have been in existence for many years. These photographs are still circulated around the world through conferences, journals and textbooks. Because of its historical sharing and publishing of images, international standards have been accepted.

By its nature, law enforcement does not distribute its images in the same manner and do not openly compare them with others around the world. This had led every agency to adopt their own methods to record images such as crime scenes, victims of assault, surveillance photographs and ‘mug’ shots.

There needs to be an effort to establish a better standard on a State, national and international level. More emphasis needs to be placed on the accurate recording of images that may prove to be valuable evidence in court. If these standards are adopted, comparison of images taken over time may be more valuable to link evidence together and possibly assist in convictions and possibly crime prevention.

Law enforcement must recognise that trained and educated photographers are specialists and should be viewed like any other law enforcement specialist profession.

Further resources

Redsicker, D.R., The Practical Methodology of Forensic Photography, CRC Press, 1994.

Smith, J., ‘Digital Imaging: A Viable Alternative to Medico-legal Photography?’, (2001) 24 Journal of Audiovisual Media in Medicine 129-31.

Spring, G., ‘Photography: Bet Your Life On It?’, (2000) 21(6) Australasian Science, Forensic Issue, Control Publications, P/L, Victoria, Australia.

Vetter, J.P., Biomedical Photography, Focal Press (an imprint of Butterworth-Heinemann), 1992.

[*] Gale E. Spring is an Associate Professor of Scientific Photography at RMIT University and Program Director of Applied Science Photography.©2001 Gale E. Spring (text).

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