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  7. Distortion in Photography in...
  • Thesis Title: Distortion in Photography in Forensic Odontology
  • Author: Jane Taylor
  • Submitted as a requirement for: Honours degree of Bachelor of Science in Dentistry
  • Date: February 1988

Abstract: Keiser- Nielsen (1980) has defined “Forensic Odontology” as that branch of dentistry which, in the interests of justice, deals with the professional handling and examination of dental evidence. Since it can involve the identification of deceased or living persons; tooth and bite mark investigations; age determination and dental traumatology, an appreciable proportion of forensic odontology work requires the use of photography for either evidential or investigative purposes. T.A Palmer-Benbow, when giving evidence at the trail into the murder of Linda Agostini, admitted that “very strange things could happen with cameras” (Coleman 1978).

That old adage “the camera never lies” actually does not hold true. Both the camera and the resultant photographs can produce misrepresentations of the truth and this is a very important consideration when the results are to be used in scientific investigations or for legal evidence. In Forensic Odontology, photographs are used mainly in the areas of bite mark investigation, craniofacial superimposition and lip print comparisons. Bite marks are perishable evidence because healing or decomposition obliterates the mark in time (Bernstein 1983) and photographs may well become the only permanent record available for analysis (Krauss 1984). The need for technically accurate results is thus imperative. The task of the photographer is to produce “something which will convey to the eye of the viewer an accurate reproduction of the scene as it would appear if the viewer actually saw the scene” (Scott 1970). The accuracy of this image is the important consideration. If it can be shown that the representations produced are accurate then the photographs can be of great value to the investigator and will more readily be accepted as admissible evidence. The study which forms the basis of this research report was undertaken in an attempt to find a system for taking photographs of acceptable detail and quality using the human skull as a model. The resulting photographs would then be used to ascertain if there was a way of determining the amount of photographic distortion, if any, introduced during the photographic process. A method of taking projected measurements of the skull was devised.

Measurements were then made from a series of photographs of the skill enlarged to life-size and the results compared. Because skulls were used as the primary source it was thought that from the results it may be possible to comment on the accuracy, and therefore validity of using craniofacial superimposition as a method of identification. Review: The major problem posed by the use of photographs is that they are two-dimensional representations of three-dimensional objects. There are many sources of errors which can manifest themselves in the final photographs. These include photographic problems relating to the equipment used, for instance the camera, lens, film and lighting, as well as to developing and equipment such as the chemicals and enlarger used (Dorion 1983). Considerations of photography in forensic literature, however, tend to concentrate mainly on errors that can be introduced in the photographic technique and on the subject matter involved.