Enhancement Of Fluorescent Fingerprints By Time-Resolved Imaging

Laser detection of latent fingerprints tends to fail when prints are located on certain types of surface, such as brown cardboard and wood, because the generally weak fingerprint fluorescence is overwhelmed by background luminescence from these substrates. The fingerprint and background fluorescence lifetimes, which are of nanosecond order, were measured for samples of the above surface types and for fingerprints treated by the most successful current detection procedures. Our results indicate that time-resolved imaging can in these situations improve image contrast by about an order of magnitude.