NCJ Number
142937
Journal
Journal of Forensic Identification Volume: 43 Issue: 3 Dated: (May/June 1993) Pages: 240-244
Date Published
1993
Length
5 pages
Annotation
A new formulation, similar to the Small Particle Reagent (SPR), was developed for latent fingerprint visualization on wet, dark objects.
Abstract
Latent fingerprints on wet, nonporous surfaces often can be visualized by use of the SPR procedure; however, since the reagent is dark, the procedure may render the developed prints difficult to detect by normal observation when they are on a wet, dark object. The substance that gives conventional SPR its dark color is molybdenum disulfide, which is the main component of the reagent. To improve the contrast of developed latent fingerprints on dark surfaces, it was necessary to find a formulation for SPR that would be based on a substance that is white or light colored. This formulation would then need to be examined to determine its compatibility with the other components of the SPR preparation and its potential to reveal latent fingerprints. The best results for contrast and ease of application were obtained with the following formulation: zinc carbonate (0.66g), water (20ml), tergitol-7 (0.06g), and dimethyl ether (55g). The primary advantage of the new method over the conventional SPR technique is the better contrast achieved on dark surfaces. Also, the aerosol spray cans designed for this study are easily carried and used by field technicians at crime scenes. 2 figures and 4 references