NCJ Number
77362
Journal
Journal of the Forensic Science Society Volume: 21 Issue: 1 Dated: (January 1981) Pages: 15-22
Date Published
1981
Length
8 pages
Annotation
This paper describes new techniques for latent fingerprint detection which are used by the Home Office Police Scientific Development Branch in Great Britain.
Abstract
A study has been conducted of the behavior of fingerprint deposits on fibrous substrates such as fabrics and paper. It is possible to detect the presence of fat films on some surfaces by the selective condensation of metals under vacuum. A range of single metals and metal combinations have been found that will delineate fingerprints. A combination of gold followed by cadmium has been originally selected as being most sensitive. To remove the toxic hazard associated with cadmium, zinc is used operationally. The small amount of gold is used as nucleation sites for zinc which does not normally condense onto nonmetallic surfaces. The size and distribution of gold under, or in, the surface depends on the nature of the surface. The variation in nuclei size and distribution affects the rate of growth of the subseqently deposited zinc film, thus delineating the fingerprint. Another effect under examination is the fluorescence of fingerprints. A 1977 and a 1978 report of work using Argon Ion lasers have become a basis of other studies. The process is effective on some surfaces but does have severe limitations; e.g., background fluorescence. The technique is however, of great interest since it is nondestructive if modest power levels are used. Other techniques are described. Photographs and 10 references are included.