NCJ Number
142348
Journal
Journal of Forensic Identification Volume: 40 Issue: 6 Dated: (November-December 1990) Pages: 349-352
Date Published
1990
Length
4 pages
Annotation
This article describes the use of ultraviolet photoreactive curing systems to recover patent grease fingerprints and powdered latent prints.
Abstract
Ultraviolet curing photoreactive systems are chemical combinations of monomers and oligomers that contain photoinitiator. Exposure to ultraviolet light causes the photoinitiator to release or form free radicals that begin the polymerization of unsaturated resins. The study reported in this article first applied these systems in patent print tests made using a thin layer of grease with a limited amount of dirt present. Five drops of system were applied to the print area and placed in direct sunlight for 5 minutes to ensure a full cure. The plastic print form was lifted from the surface and washed in warm water and a mild hand soap to remove remaining grease. Once dry, the plastic print form was powdered and tape applied, recovering an identifiable print of high optical quality that can be left in place and viewed through the back side. No damage was done to the grease print. Another set of tests was made with system applied over powdered latent prints. The coating acted as a liquid "tape" that protected the latent print from damage. It can be lifted or left on the item as needed. Magnetic powder became part of the system and could not be washed off with soap and water. 3 figures