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Toneline Bite Mark Photography

NCJ Number
Date Published
January 1992
13 pages
In bite mark analysis, the initial photograph is critical for the collection and presentation of evidence. A high-contrast film technique previously used primarily in the graphic arts field has been refined and applied to forensic odontology.
In developing the technique, the investigation concentrated on looking for the optimum negatives to be enlarged onto lithographic film to achieve a black "pen-and-ink" line around the bite mark. The researchers also wanted to demonstrate the subjective qualities of currently accepted examination methods. The investigation involved 14 bite marks. Five were self-inflicted by a researcher because of a lack of timely coroner cases; nine were present on four decedents. The study produced 716 panchromatic film negatives (51 per bite mark), 463 orthographic film positives (33 per bite mark), 67 orthographic film negatives (5 per bite mark), and 23 toneline film positives (2 per bite mark). The toneline process reduced interpretational bias and yielded a transparent overlay with a photographic outline of the bite mark which could be directly compared with models of the suspect's teeth. It was determined that toneline photography is inexpensive and can be easily duplicated. The technique, however, has problems in that there is a loss of detail in shadows and it does not always work. 23 references. 2 tables, and 6 figures (Author abstract modified)

Date Published: January 1, 1992