NCJ Number
225896
Journal
Journal of Forensic Sciences Volume: 54 Issue: 1 Dated: January 2009 Pages: 114-121
Date Published
January 2009
Length
8 pages
Annotation
This article reports on the development of a new refinement of the technique of using heat alone in order to develop latent fingerprints on porous surfaces such as paper.
Abstract
The study found that very rapid heating in dry air in the vicinity of 300 degrees C will successfully develop latent fingerprints on paper in two stages: an ultraviolet-fluorescent (but otherwise invisible) fingerprint is developed after short heating times; and a visible fingerprint with excellent ridge detail and contrast is developed after further heating. After a short heating time, the fingerprint ridges fluoresced under 505 nm illumination and could be observed using a 450-mm filter. Longer heating times generally led to dark brown-colored development of the fingerprint ridges, typically against a pale brown (scorched) background of the rest of the paper. Further heating caused loss of ridge contrast as all of the paper turned dark brown before it combusted or disintegrated. The chief advantage of thermal development of latent fingerprints on porous surfaces such as paper is that no chemical reagents are required. This means that the cost and health/environmental issues associated with the use of reagents are removed. In addition, the ease and speed of fingerprint development aids in the development of higher volumes of samples. In addition, minimal training or expertise is required to develop fingerprints thermally. The procedure used involved depositing fingerprints on various papers and then attempting to develop them by exposing them to hot air with a temperature in the vicinity of 300 degrees C for periods of approximately 10-20 seconds. Several different heating methods were tested. 11 figures and 11 references