Surface-Dependent Optimization of Gold Evaporation Time in Vacuum Metal Deposition for Latent Fingerprint Visualization

This study aims to determine the optimal gold evaporation time in Vacuum Metal Deposition (VMD) processes used for developing latent fingerprints on non-porous surfaces. VMD is a highly sensitive technique that visualizes latent fingerprints through the sequential deposition of gold and zinc under high vacuum conditions. In this research, the effects of gold evaporation duration were analyzed on two types of surfaces: glass slides and PVC book covers. Using the IDENTICOAT 500 VMD system, gold wires and zinc plates were vaporized under controlled conditions, and fingerprint development was evaluated at three different gold evaporation times (5s, 10s, and 15s). The quality of developed fingerprints was quantitatively assessed using parameters such as contrast, brightness, signal-to-noise ratio, and minutiae visibility. The results indicate that a gold evaporation time of 10s yielded the most effective development for both surface types. These findings highlight the importance of optimizing material-specific VMD parameters to enhance fingerprint visualization. Future studies should explore a wider range of substrates and experimental conditions to further refine the VMD process