ABSTRACT
The act of writing upon pages that are stacked together may leave indented writing or impressions on the lower sheets. The depth of any impression will depend on the applied pressure, the writing instrument, the nature of the paper, and the writing surface support. Over the past 100 years, forensic document examiners have used a variety of means to visualize and record indented writings on paper and other substrates. Many techniques that have been proposed are not generally used today as they are destructive to the document or render the development by other means impossible. Even without directional illumination, it is often possible to see indentations on a page when conditions permit. Sometimes simply having the document on a table with daylight from a window may permit viewing of indentations. More complex filters that may reduce effects of background noise and interfering portions can also be used.
