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Impression lab

The impression/tire track lab was a very unique look at impression evidence. During the lab, we ran various toy “matchbox” cars over an ink pad, then in boxes on our sheet of paper. We looked at each print to determine the specialities and then match it. This was a detailed study of the 2-D impression. The tire tracks varied in pattern, period (length of repetition), and width. The tracks were not perfect: some parts were missing and parts had more ink than other places. The two hard surfaces and plethora of ink made these impressions straightforward, but the variables that come with soft or malleable surfaces, or incomplete prints are imaginable. A muddy footprint would be very difficult to work with, for example. The shoe print may not be fully deep as the person was only running on the balls of their feet. They may have twisted their foot in the mud, obscuring the tracks and shoe size. Conditions like rain or other footprints could even completely erase it. Like ballistics, impression evidence is very difficult to work with at some times, and professionals have huge risk for error, where an exact match is almost impossible.


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