NCJ Number
215159
Journal
Journal of Forensic Sciences Volume: 51 Issue: 4 Dated: July 2006 Pages: 908-914
Date Published
July 2006
Length
7 pages
Annotation
This paper describes experiments that build upon Van den Heuvel's approach of using a black gelatine lifter slab to create an image of indented writing, comparing the results with those obtained from an electrostatic detection apparatus (ESDA) and oblique lighting.
Abstract
Raster electron microscopy (REM) examination of indentations before and after gelatine lifting showed that before gelatine lifting, a high concentration of paper dust particles from the paper filler was found in the indentation groove. After gelatine lifting, the concentration of filler particles in the indentation groove was not much different from that outside of the groove. Electrostatic detection following gelatine lifting showed a substantial overall deterioration in the results obtained. Gelatine lifting following electrostatic detection showed no significant deterioration in result. In some instances, the results improved due to a decrease in the background dust image. Based on the experiments described in this paper, the authors conclude that gelatine lifting should be performed after electrostatic detection, since there is a significant deterioration in the ESDA lift after gelatine lifting. This procedure is particularly suitable for glossy-coated and printed paper types. The gelatine lifting method outperformed oblique lighting for the detection of indented writing, and was almost as sensitive as electrostatic detection when compared on the types of paper where both performed well. The main advantage of this new technique is its suitability for those types of paper where electrostatic detection fails. The method described uses black gelatine lifter slabs to lift the paper dust image off the surface of the paper. This image is easily photographed with the use of near-to-coaxial lighting. 5 tables, 11 figures, and 6 references