Types of Fingerprints

Latent Fingerprints

The word latent means hidden or invisible but in modern  forensic science the term latent prints refers to any accidental impression left by friction ridge skin on a surface, regardless of whether it is visible or invisible. Electronic, chemical and physical processing techniques permit visualization of invisible latent print residues whether they are from natural sweat on the skin or from a contaminant such as motor oil, blood, ink, paint or some other form of dirt. Latent prints may reveal only a small portion of the surface of a finger and may be smudged, distorted, overlapped by other prints (from the same or from different individuals), or any or all of these in combination. For this reason, latent prints are said to present an “inevitable source of error in making comparisons,” since they generally “contain less clarity, less content, and less undistorted information than a fingerprint taken under controlled conditions, and much, much less detail compared to the actual patterns of ridges and grooves of a finger.”

Invisible prints revealed by ultra-violet light

 Plastic Prints

 A plastic print is a ridge impression left in a material that retains the shape of the ridge detail. Leaving prints in a lump of wet clay would make a perfect plastic print. Commonly encountered examples are melted candle wax, putty removed from the perimeter of window panes and thick grease deposits on car parts. Plastic prints are already visible and need no enhancement, and are easily photographed to be referred to later.

Plastic print left in clay

 Direct Prints

Direct prints, or known prints, are fingerprints intentionally collected from a subject for purposes of enrollment into a system or arrest of a suspect involved in a criminal offense. During criminal arrests, a set of direct prints will usually include one print taken from each finger, plain (or slap) impressions of each of the four fingers of each hand, and plain impressions of each thumb. Direct prints can be collected using Digital Live Scan or by using ink on paper cards.

Visible prints from ink