Visualization of latent Fingerprints using metal thin-films
The commonly used detection and preservation of latent fingerprints methods employ dry powders or wet chemistry principles to visualize the samples in the field and also for laboratory analysis. This research examines a rarely-used technique to visualize latent fingerprints with a secondary purpose of preservation as the sample fingerprints may be exposed to extreme conditions. The method employs physical vapor deposition of silver deposited on glass, plastic, paper and metal substrates. Varying thicknesses of silver ranging from 1.0 nm to 10.0 nm are deposited on substrates and examined for optimal spectral, transmittance and reflectance signals. Subsequent analysis repeats the spectral examination of latent fingerprints contained on the surfaces after the vapor deposition and addresses the optical properties and visualization methods of fresh and weathered latent prints.