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تسجيل

WHEN FOOTWEAR TOUCHES THE GROUND

المؤلف:  Max M. Houck، Jay A. Siegel

المصدر:  Fundamentals of Forensic Science

الجزء والصفحة:  P580-581

2026-09-06

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WHEN FOOTWEAR TOUCHES THE GROUND

A number of things can happen when footwear touches the ground. First, a static electricity charge can be applied to the impression if the shoe is clean and dry. This charge dissipates after a short time but is useful because it helps in the transfer of trace residues and dust to the impression. If the surface is soft or pliable, pressure exerted by the foot will cause the surface to deform and take on the contours of the surface of the footwear. If the surface is dirty or snow, the impression may be long lasting. If the surface is grass or carpet, the impression may be quite transitory. Even in cases where the impression is temporary, trace residues may be transferred to it. As mentioned previously, if the footwear surface contains unique characteristics, they may be transferred to a pliable surface of sufficient resolution to capture small features such as the wear and tear on shoe soles and heels that they accumulate with use. Figure 1 shows a shoeprint that was made in soil.

FIGURE 1 A shoeprint that was left in soil at a crime scene.

An imprint is where there is enough residue on the footwear to leave an impression on the recipient surface. This would be a positive impression because the residue is on the surface of the footwear that touches the surface. Positive impressions are the most common type of footwear imprints. If the shoe sole is clean and the recipient surface contains a lot of dust or residue, then a negative impression can form. Here the parts of the shoe that touch the floor remove the residue, leaving behind a negative impression. Imprints also result when someone tracks through blood, wet paint, or grease. Depending upon how much of this material is present, a negative impression may be left in the liquid and a positive impression may be deposited further away on a clean surface from the residue picked up by the shoe.