A fingerprint is a mark left behind after the ridges on the fingers, hands, toes or feet touch an object. There are two types of prints: a direct fingerprint (it creates an impression) and a latent print (dirt, sweat or other residue that is pressed onto another object). Fingerprints have three main classes: the arch, whorl and loop. Within these three classes, there are an immense number of patterns that are different for each one of us. Aside from scars, there are forks, islands or spaces where the lines of a fingerprint make different latent prints.
No two fingerprints are the same. Fingerprints can be taken even from surfaces which are not smooth (e.g. clothing or paper towel). Even if fingerprints are months or years old, new technology allows scientists to recover fingerprints from objects. Techniques using charged particles or particles that glow under certain conditions are applied to test areas. This allows for testing of larger areas and faster processing of fingerprints at the crime scene.
