A comparison of six fingerprint enhancement techniques for the recovery of latent fingerprints from unfired cartridge cases

This work compared the effectiveness of six different enhancement methods on six different sizes of brass cartridges. One sebaceous fingerprint was deposited onto twenty-five of each size of cartridge to enable a statistical evaluation of the enhancement methods for each cartridge size to be undertaken. The enhancement methods compared were superglue followed by BY40, superglue followed by gun blue followed by BY40, gun blue only, superglue followed by palladium deposition, palladium deposition only, and powder suspension. The six different cartridges used in this study were .22s, .32s, 9mm, .38s, ribbed shotgun, and smooth shotgun. The study found that more potentially identifiable fingerprints were enhanced on the larger cartridge cases. This was due to the surface area on the smaller cartridges, and in particular the .22s provided little ridge detail. Two techniques provided the best results - superglue followed by gun blue followed by BY40, and superglue followed by palladium deposition. This showed that the combination of the cyanoacrylate fuming and the metal oxidation reactions is increasing the yield of potentially identifiable fingerprints compared with the use of the techniques separately. Both techniques were also found to give reproducible results. These two enhancement techniques were also compared statistically and no statistical difference in their effectiveness was found suggesting both techniques are equally as effective at enhancing fingerprints on brass cartridge cases