Forensic Applications of Chemical Imaging: Latent Fingerprint Detection Using Visible Absorption and Luminescence

• NCJ Number: 203119
• Journal: Journal of Forensic Sciences Volume: 48 Issue: 5 Dated: September 2003 Pages: 1047-1053
• Author(s): David L. Exline M.S.; Christie Wallace B.Sc.; Claude Roux Ph.D.; Chris Lennard Ph.D.; Matthew P. Nelson Ph.D.; Patrick J. Treado Ph.D.
• Date Published: September 2003
• Length: 7 pages
• Publication Format: Article
• Publication Type: Report (Study/Research)
• Language: English
• Country: United States of America

Annotation

This study investigated the potential of chemical imaging to increase the contrast and visual quality of fingerprints compared to current methods of detection.

Abstract

The major difference between chemical imaging and conventional methods of latent fingerprint detection is the use of a liquid crystal imaging spectrometer. Analysis can be performed with less than 1-nm increments from 400 to 720 nm, greatly increasing flexibility in achieving the optimal collection wavelengths, ultimately increasing the sensitivity of the analysis. Contrast is generated in the images based on the relative amounts of light that are produced by the various species located throughout the sample. Since a spectrum is generated for each pixel location, chemometric analysis tools such as principle component analysis and multivariate curve resolution can be applied to the image data to extract pertinent information otherwise missed by ordinary univariate (single wavelength) measures. In the current study, latent fingerprints of various ages transferred to both plastic and paper supports were placed on the CONDOR Macroscopic Chemical Imaging system sample stage. Chemical images were captured in the absorption mode over the range 400 to 720 nm at 5-nm increments. Illumination of the samples was by white light from a 300W xenon arc lamp. The camera was a thermally cooled slow scan 512 by 512. The spectral range where the maximum contrast existed was identified from the imaging data. A background analysis was also conducted for the paper support. Luminescence chemical imaging and visible absorbance chemical imaging were successfully applied to ninhydrin, DFO, cyanoacrylate, and luminescent dye-treated latent fingerprints. This demonstrates the potential of this technology to aid in forensic investigations. In addition, visible absorption chemical imaging was successful in visualizing untreated latent fingerprints. 4 tables, 12 figures, and 7 references