NCJ Number
203507
Journal
Journal of Forensic Sciences Volume: 48 Issue: 6 Dated: November 2003 Pages: 1314-1317
Date Published
November 2003
Length
4 pages
Annotation
This article discusses a method for enhancing contrast of fingerprints.
Abstract
Many different methods are available to visualize fingerprints on tape. These techniques typically rely on creating a visual difference between the fingerprint and the background on which it is located by coloring the fingerprint itself. In most cases, these techniques require that the contrasting agent chemically reacts or interacts with the fingerprint. This may be damaging to the print. The methods explored in this study differ from the traditional methods in that the intent was to produce contrast by shading the background with distinct visual color. A sublimation process was used, with disperse dyes providing coloration to the background of fingerprinted tape samples, minimizing physical interaction with the fingerprint. Fuming with disperse dyes was no more difficult in execution than the existing methods for resolving fingerprints on plastic tape and there were benefits specific to this method. The dyes used penetrated into the tape, dyeing it, giving a permanent inverse image of the fingerprint that would not wash or rub off. As long as a resistive layer remains on the surface of the tape, sublimation grade disperse dyes can be used to provide differentiation even after the biologic matter in the print has broken down. Because the dyes color the tape rather than the fingerprint, this method can provide differentiation of fingerprints made with a variety of mediums. The best results were obtained by using a two-step process: fuming first with the cyanoacrylate and then fuming with a disperse dye. This two step process yielded excellent resolution, even on the difficult substrate of black electrical tape, and excellent visualization without the need for special light sources. 6 figures, 7 references