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Erasures

المؤلف:  Max M. Houck، Jay A. Siegel

المصدر:  Fundamentals of Forensic Science

الجزء والصفحة:  535

2026-08-25

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Erasures

Erasures can occur in a number of ways. The familiar abrasive erasure involves removing writing (usually that made with a pencil) with an abrasive eraser material. Chemical erasures involve dissolving or bleaching ink so that it is no longer visible. Typewriter erasures involve the use of a ribbon that lifts typewritten images from the paper. All of these erasure types can, in principle, be detected. Abrasive erasures are the easiest to detect. They virtually always involve disturbance of paper coatings and fibers at the point of the erasure that can be seen with a low power microscope. Chemical erasures may be detected by differences in shades of color in the paper   from bleaching effects or by behavior of the chemicals in UV or IR light. Typewriter erasures can be detected by observing the indentations made by the typewriter in the paper. This can be done using oblique-angle photography and a low power micro scope. Even though it may be relatively easy to detect that an erasure has taken place, it is usually more difficult to determine what was erased. An efficient erasure may be impossible to overcome and the writing may never be reconstructed. Partial erasures may enable the examiner to read some or all of what was erased as seen in Figure 1.

FIGURE 1 Erasures. Original documents read “6% interest….” (a) A pencil erasure. (b) A typewriter erasure (c) A chemical erasure.