تسجيل الدخول

تسجيل

Lifting imprints

المؤلف:  Max M. Houck، Jay A. Siegel

المصدر:  Fundamentals of Forensic Science

الجزء والصفحة:  p584-586

2026-09-07

33

Lifting imprints

An imprint in a material like dust or one that has been visualized using a powder technique analogous to fingerprints can be lifted from a surface in a number of ways. One can use large pieces of tape just as would be done on a smaller scale with fingerprints or palm prints. There are also gelatine materials made especially for lifting prints. The most popular method used today, however, involves one of a number of electrostatic lifting devices. The principle behind these techniques is that a large, static electricity charge will strongly attract dust and other fine powders.

A low-current, high-voltage charge is put across a film that attracts the particles from the impression, thus affecting a transfer. A contrasting color film can be used as the transfer surface. The transferred image can then be easily photographed. Figure 1 is an electrostatic lift of a shoeprint that was made in dust. Some imprints are difficult or impossible to lift. These include those in grease or oil or in blood. There are also impressions made in materials that deform when impressed but then bounce back and lose the impression, such as cushions or carpeting materials. The three-dimensional image would be lost when the substrate regains its shape but there may be residues imbedded in the impression that form an imprint that may, in some cases, be lifted. Figure 2 is a picture of a shoeprint that was made in blood at a crime scene.

FIGURE 1 An electrostatic lift of a shoeprint left in dust.

FIGURE 2 A shoeprint left on a floor after the wearer stepped in blood at a crime scene.