NCJ Number
236578
Journal
Journal of Forensic Identification Volume: 61 Issue: 6 Dated: November/December 2011 Pages: 621-639
Date Published
December 2011
Length
19 pages
Annotation
This article discusses physical developer (PD) a widely used chemical processing technique for the development of latent prints on dry or wetted porous surfaces.
Abstract
Physical developer (PD) is a widely used chemical processing technique for the development of latent prints on dry or wetted porous surfaces. The objective of Part I of this research was to verify that the United States Secret Service (USSS) formulation for PD will outlast the 7-10-day shelf life that is mentioned by some practitioners. The USSS recently changed the nonionic surfactant from Synperonic N to Tween 20, which appear to have improved the longevity of the working solutions. This research compared fresh and aged batches of working solutions using both nonionic surfactants and determined that PD working solutions incorporating Synperonic N had a shelf-life ranging from 10 to 15 days, whereas PD working solutions incorporating Tween 20 had a shelf life of approximately two and one half months. In addition, Part II of this research will discuss the importance of reliability testing to determine the stability of the reagent and comparisons conducted between two different reliability test solutions, gold chloride (AuCl3) and EDTA tetra sodium salt. (Published Abstract)