NCJ Number
162856
Journal
Journal of Forensic Sciences Volume: 41 Issue: 1 Dated: (January 1996) Pages: 80-93
Date Published
1996
Length
14 pages
Annotation
This study examines the sequence of crossed lines, using a scanning electron microscope and photographic stereoscopic pairs.
Abstract
Document examiners are frequently asked to determine whether the printed/typewritten text or the signature/handwritten text was placed on a document first. In this work, the documents examined were green background printed checks bearing light, poor quality typewritten impressions from an old, dry fabric ribbon, probably produced on an old portable typewriter. The handwritten signatures (crossing) were made with light green ink and very light pressure from a ball point pen. Examination by conventional, nondestructive, light optical methods gave no conclusive results. The authors used a Hitachi S-2500 SEM, which can be operated at accelerating voltages ranging from 0.5 to 30 KV. It is equipped with two secondary electron detectors: upper, which is used for imaging very minute details; and lower, which is used in most routine SEM work and yields good, normal electron micrographs. The authors found that an accelerating voltage of 5 KV together with the upper electron produced the most useful and informative electron micrographs. Figures, references