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La Revelation Des Traces Papillaires Sur Les Douilles Par Les Techniques De Etching Et De Blueing Et Comparaison Avec La Deposition Multimetallique

NCJ Number
Canadian Society of Forensic Science Journal Volume: 33 Issue: 2 Dated: June 2000 Pages: 65-81
F. Schutz; M. Bonfanti; C. Champod
B. Yamashita
Date Published
June 2000
17 pages
Etching and blueing processes are techniques used to reveal finger marks on cartridge cases, and these techniques are based on oxidation-reduction reactions.
The efficiency of these reagents was tested on five types of cartridge cases (brass, nickeled brass, aluminum, copper, and lacquered steel) and was compared with multi-metal deposition (MMD). Seven techniques were tested on each cartridge case--MMD, two etching techniques, and four blueing techniques. The latter were characterized by an etching process in which the metal of the cartridge case was solubilized, and a dark complex was them formed and deposited on the cartridge case (blueing process). Results showed a greater efficiency for blueing techniques, particularly for the treatment of sebaceous fingerprints. Etching or MMD offered, in some cases, a better quality of fingerprint details, avoiding over-development especially for etching. Concerning MMD, it appeared that only the physical developer contributed to finger mark detection. An optimization of the physical developer could enhance its performance on this specific surface, for example, by reducing its speed of reaction. Cartridge cases made of aluminum or lacquered steel remained problematic surfaces for detecting finger marks deposited on their surfaces. 20 references, 11 tables, and 2 figures