NCJ Number
224721
Journal
Journal of Forensic Sciences Volume: 53 Issue: 5 Dated: September 2008 Pages: 1108-1116
Date Published
September 2008
Length
9 pages
Annotation
Because of the variability achieved worldwide in using 1,2-Indanedione (Ind) in processing latent fingerprints, which has shown potential for enhanced fluorescence, this study identified the cause of the variable results and developed an improved method for using Ind in processing latent prints.
Abstract
In the laboratory where this study was conducted, results achieved with Ind were apparently influenced by fluctuations in ambient relative humidity (% RH). Determination of visible color and fluorescence as it corresponded to percentage moisture content allowed for defining critical threshold levels necessary for achieving optimal results with Ind. If the defined substrate-specific critical % RH value was exceeded, the samples were best processed using a laboratory oven; if the % RH values fell below this level, most optimal results were achieved using a humidity chamber. The critical moisture value was found to be that measured after the paper had been processed and allowed to dry for 10 minutes, which was directly impacted by both the dwell time in the reagent and the % RH of the surrounding air. When proper processing protocol was followed, dipping in the solution for a period not to exceed 5 seconds, any variability contributed by this component was eliminated, leaving only the % RH differences as significant for variability in results. Thus, using the appropriate processing method for the % RH in the laboratory, an optimized Ind-Zn formulation that contained petroleum ether as a carrier solvent and 7.4 percent v/v ZnCl2 performed better both in initial color development and fluorescence than did DFO (1,8-diazafluoren-9-one) for prints ranging from those freshly deposited to 11 years old. The methods used in conducting this experiment are described in detail. 8 figures and 20 references