For this reason they have long been studied by police and crime laboratory personnel. There is no doubt that a comparison of a shoe trace found at the scene of crime obtained from a defendant can be a valuable ink associating the defendant with a crime. The question that is more difficult to answer is whether a particular shoe trace can be positively identified as having been made by a specifific item of footwear. The science of footwear investigations is evolving now, since more research groups are working on shoeprints. Shoe prints may be found as either prints or impressions.
Prints are two-dimensional, made by depositing or removing material from a hard surface.
Impressions are three-dimensional and made in a pliable material. Both class and individual characteristics are present in each of the two types of trace evidence and are identifiable. For prints lifting with foil and photography is the major technique, and is often combined with casting for impressions. In Europe many specialists on footwear identification exist. The examiniation and comparison of impressions of footwear seens to be done mostly by toolmark and fingerprint examiners.