Latent fingerprint detection using fluorescent powder dusting technique

Abstract

This study examined the use of fluorescent powder in detecting latent fingerprints through the dusting method. Five colors of fluorescent powder (orange, green, blue, green-yellow, and red) were applied to photo papers of six colors (green, red, blue, yellow, white, and black). The fluorescence of latent fingerprints was detected using various light sources including UV LED, blue LED, green LED, red LED, warm white, and cold white. The spectra of the light source and the fluorescence intensity of the dusting powder were analyzed to determine their influence on the appearance of latent fingerprints. The fingerprint images were analyzed by counting the number of important points that are more than 7 points, which indicates visible fingerprints. The results showed that the fluorescence of the powder, background, and light source affected the appearance of the fingerprints. When the color of the fluorescent powder matched the color of the light source, the fingerprints were clearly visible. However, if the background color matched the light source, the fingerprints were not visible. When fluorescent powder was dusted on a dark or non-fluorescent background, fingerprints were visible under all light sources. This study suggests that selecting the appropriate color of fluorescent powder and background is crucial for the detection of latent fingerprints using the dusting method.