Friction Ridge Analysis

Friction ridge analysis or otherwise known as fingerprint analysis is the development and comparison of people's ridge markings either against a database or manually by a fingerprint expert, usually in response to a crime to see if that person has been caught for another crime or has their fingerprints on the data base for some other reason. The human body's friction ridge skin is found on the fingers, thumbs and palms of the hands as well as the soles of the feet and toes of a person.
The recording or printing of prints was done using printers ink for over a century, more recently that system has been replaced by a computerized system called livescan. The switch has vastly increased the quality and reliability of prints.
The main types of prints analysed are called latent prints. Although latent means hidden or not visible all unintentional impressions are referred to as latent prints.
The 4 main types of unintentional prints left are:
  • Invisible or true latent prints- composed of perspiration, oils & waxes that are naturally given off by the body. These usually require development such as powder to be seen.
  • Visible prints- in things like blood, ink, paint or another visible medium
  • Molded or plastic fingerprints- moulds or impressions in substances including: grease, butter, wax or putty
  • Etched- the impressions erode into metal due to the corrosive compounds in natural excretions, such as amino acids.

There are three main types of patterns that occur on the friction ridge skin. Some people have all three, only one or a mix of two or more. These are:
  • The arch pattern- ridges flow from left to right with a slight rise or hill in the centre of the pattern
  • The loop pattern- one or more of the ridges enter recurve and terminate, or tend to terminate on or toward the same side of the impression from where the ridge or ridges entered
  • The whorl pattern- has two deltas or triangular shapes and at least one ridge making a complete circuit which is spiral, oval or circular in shape.

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