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Toneline Bite Mark Photography

NCJ Number
Elizabeth Robinson; James Wentzel
Date Published
6 pages
Toneline, a high-contrast film technique previously primarily used in the graphic arts field, has been refined and applied to forensic odontology.
The process yields a transparent overlay with a photographic outline of a bite mark that can be directly compared with models of a suspect's teeth. It is inexpensive and reduces the interpretational bias of the investigator. Research was conducted on 14 bitemarks (nine present on four decedents, five self-inflicted), producing 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 procedure was found to work better on black skin than on white skin, and usually, but not always, yielded useful toneline overlays; whenever it failed, it did so totally, yielding no usable information. Another portion of the research exposed disparities in examiners' results when using current methods, underscoring the subjective nature of those methods. 25 references. (Author abstract modified)