NCJ Number
224404
Journal
Journal of Forensic Identification Volume: 58 Issue: 5 Dated: September/October 2008 Pages: 600-614
Date Published
September 2008
Length
15 pages
Annotation
This study compared the performance of vacuum metal deposition (VMD) and white-powder suspension in the recovery of fingerprints from wetted nonporous dark substrates.
Abstract
The study found that the powder-suspension technique was more successful in developing more potentially identifiable prints than the VMD technique for deposition on black bin bags and cowlings (removable engine coverings). The value of using the powder suspension technique was particularly relevant for cowlings, where it significantly outperformed VMD. The performance of the white-powder suspension was particularly superior to VMD for prints that had aged 14 days. The prints developed with VMD were not as easy to see as those developed by Wetwop, and various lighting techniques were necessary to view the ridge detail that was present. Both techniques, with the exception of powder suspension at 14 days, developed a large number of visible prints on orange plastic bags, with VMD recovering slightly more visible prints across all print ages compared with Wetwop. VMD proved to be more effective in developing a larger number of prints that contained more than 1/3 ridge detail (grades three and four). VMD also proved to be a more sensitive technique for clear sandwich bags across all ages, recovering all but 2 of the 280 half prints that were deposited. In addition, VMD developed a larger percentage of potentially identifiable prints (grades three and four). Various types of substrates representative of common nonporous materials were examined. These included black bin bags, orange carrier bags, clear sandwich bags, and black cowlings. These descriptions of materials and methods address the preparation of samples and the fingerprint development processes with powder suspension and VMD. 6 figures, 6 tables, and 12 references