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DOCUMENT ALTERATIONS Obliterations

المؤلف:  Max M. Houck، Jay A. Siegel

المصدر:  Fundamentals of Forensic Science

الجزء والصفحة:  534

2026-08-25

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DOCUMENT ALTERATIONS Obliterations

Obliteration is the overwriting of a sample of writing or printing with another writing instrument. It may be accidental or deliberate. The document examiner may be called upon to discover what is contained in the writing beneath the obliteration. Obliterations can be made with pens or pencils or other types of writing instruments. The method used to discover what is written under an obliteration depends on the original writing and the means used. It may be possible to dis solve all or part of the obliteration or to use a light source that will be transmitted through the obliteration but not the original writing. This will permit the examiner to read the original writing underneath the obliteration. In some cases, it is possible to treat the paper with a special transparent liquid that changes its refractive index so that the original writing can be viewed from the back of the paper. In some cases, a strong backlit light source may penetrate the obliteration enough to read the underlying writing. A sample of obliterated handwriting is shown in Figure 1(a) and (b). Over the past 10 years, one of the authors of this book encountered cases in which sections of printed documents were obliterated using a black marker. In one case, soaking the document in methyl alcohol removed enough of the marker to see through it without damaging the printing below. In another case, ethyl alcohol did the same thing. Such soaking techniques may not be successful if the original writing is made with ink as opposed to toner because the solvent used to dissolve the obliterating agent may also dissolve the ink. The use of infrared (IR) or ultraviolet light may visualize underlying handwriting that has been obliterated. The wavelength of light is chosen so that it is transmitted through the obliteration to the ink below. If the ink then absorbs the light, it will appear dark. Sometimes the light will cause the ink to fluoresce in the visible or IR region enabling it to be seen with the naked eye or a camera and special film or filters.

FIGURE 1 Obliteration. (a) A portion of a patient’s medical record with an entry obliterated. (b) The same record photographed with infrared light.