Latent fingerprints on cartridges and expended cartridge casings.

The effects of time and detonation on latent fingerprints from cartridges and cartridge castings were explored. Time alone did not appear to seriously degrade latent fingerprint quality over the three-week period of experimental trials. The greatest effect of detonation seemed to stem from hot gaseous blowback on the external surface of the cartridge casings. Nickel-plated casings, because of their greater chemical resistance and more polished surface, were found less satisfactory as a substrate for latent impressions than brass casings. An interesting technique for development and permanent preservation of latent fingerprint impressions on castridge casings was also described.