Photographic Imaging Distortion and Its Effects on Forensic Bite Mark Analysis

A systematic review of the literature was completed to fi nd relevant materials to analyse the effect of photographic distortion in the analysis of forensic bite marks. A total of 12 key pertinent references were found and formed the basis of this review. Photography has been used as a medium of expression and also to document events. It has been used in many disciplines, each with their own specifi c requirements. It has also been used widely in dental forensics, frequently for recording and subsequent analysis of bite mark evidence. Recent developments in the fi eld of digital imaging and image capture have allowed forensic examiners to use the computer as a ‘comparative microscope’. Digital imaging is useful in documenting and recording the immediate surroundings of both the crime scene and the evidence. Image distortions can occur however because of poor photographic techniques; hence the image can no longer be used and has to be re-photographed subject to availability of the person suspected of infl icting the bite mark. There are two types of distortions; primary and secondary. Primary distortion occurs at the time the bite is infl icted. The major contributions for primary distortion come from both the dynamics of the biting process and the level of detail on the tissue being bitten. Secondary distortions are those that are found at a later stage and not immediately after a bite. One has to consider the fact that using digital imaging has both advantages and disadvantages, the primary advantages being that it is time saving. It can be disadvantageous when distortions occur in bite marks, but the limitation these distortions present during bite mark analysis is never too small. The presumption that a photograph of a bite mark that is distorted can be altered will remain a presumption for years to come.