NCJ Number
217215
Journal
Journal of Forensic Sciences Volume: 52 Issue: 1 Dated: January 2007 Pages: 48-53
Date Published
January 2007
Length
6 pages
Annotation
This study examined the ability of Fourier transform infrared (FTIR) spectroscopic imaging to reveal latent fingerprint details on challenging substrates without preprocessing or pretreating the latent prints.
Abstract
The study found that FTIR imaging revealed untreated latent fingerprints on various nonporous and porous substrates without altering the state of the evidence. Various analysis techniques--including band intensity, the addition and subtraction of band intensity, principal components analysis (PCA), and second derivative band intensity--were used to improve the print images on the substrates. In addition to detecting fingerprints, FTIR also provided additional forensic information such as a fiber within a fingerprint on a postcard, and the chemical components of inks on paper money. This method works well when the forensic scientist knows where to look for latent fingerprints. Fingerprints were deposited onto substrates that included trash bags, a soda can, and tape (nonporous) and copier paper, cigarette butt paper, a U.S. dollar bill, and a postcard (porous). Both visible and infrared reflectance images were obtained by using a Spectrum Spotlight 300 FTIR Microscope System with a 100 mm x 100 mm microscope aperture. Once acquired, all spotlight infrared images were imported into ENVI software by using an in-house written program that converted the Perkin Elmer data format into a data format transferable to ENVI. 1 table, 9 figures, and 34 references