ISSN: 0022-1198
CODEN: JFSCA
Page Count: 3

Photographically Subtracting Interfering Images from ESDA Print
Hart, LJ
Questioned document examiner, Hart Questioned Document Laboratory, Inc., FL

Hart, RP
Proprietor, Florida Forensic Photography, FL

(Received 2 December 1988; accepted 28 December 1988)

Abstract

Documents containing indentations from other written papers may also contain original written material on the reverse side of the page. When such a document is processed on an Electrostatic Detection Apparatus (ESDA), both the subject indentations and the writing on the reverse of the paper are often recorded. It is usually very difficult to decipher the indented writing because of the overlapping images from the reverse of the paper. It is possible, however, to subtract these interfering images by making a positive transparency of the original writing on the reverse of the paper and sandwiching it with a negative of the ESDA. This method provides a clear and accurate record of the subject indentations alone.

Keywords:
questioned documents, electrostatic detection apparatus (ESDA), indentations

Paper ID: JFS12782J
DOI: 10.1520/JFS12782J
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