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Indented Writings

المؤلف:  Max M. Houck، Jay A. Siegel

المصدر:  Fundamentals of Forensic Science

الجزء والصفحة:  p535-536

2026-08-26

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Indented Writings

There are many situations where a document is written on the top sheet of a pad of paper using a writing instrument, such as a ballpoint pen, that exerts pressure on the paper. This may result in an image of the writing being formed on one or more pages below.

There are a number of ways of viewing this indented writing. The simplest and most popular method of viewing indented writings is with oblique lighting. If a light is directed across the surface of the page at an angle, the indentations may cast enough shadow on the paper to reveal the contents of the writing. This may work for several pages below the top sheet, especially if a high-resolution digital camera is used to capture the image. Sometimes TV or movies will show indented writing being visualized by rubbing the indented area with the side of a pencil. This will not only usually fail to visualize the indented part of the writing, but will destroy the evidence also so that workable methods cannot be used. There is also an instrumental method for capturing indented writings. It is called the Electrostatic Detection Apparatus (ESDA). This apparatus works a bit like an electro static copy machine, in that it uses a toner that is deposited preferentially in the indented writings so that they can be visualized. Figure 1 illustrates how ESDA is used.

FIGURE 1 The use of an electrostatic detection apparatus (ESDA). This is a note given to a bank teller during a robbery. ESDA reveals what was written on the piece of paper above the note in the pad of paper on which the note was written.