Fingerprints

There are three types of patterns associated with fingerprints. They are:

Each of the three pattern types have points which are used for classification. There are two different types of points, cores (the centre of a loop) and deltas (the area where there is a triangulation a dividing of the ridges).


In the loop pattern, there is 1 core and 1 delta.
In the whorl pattern, there are two deltas.

There are no cores or deltas in the arch pattern

There are two types of impressions involved in taking fingerprints. The upper ten impressions are taken individually, thumb, index, middle, ring, and little fingers of each hand. These are referred to as the "rolled" impressions because the fingers are rolled from one side of the fingernail to the other.

The impressions at the bottom of the card are taken simutaneously without rolling, printing all of the fingers of each hand at a forty-five degree angle and then the thumbs. These are referred to as "plain," "slapped," or "flat" impressions. The plain impressions are used to verify the rolled impressions.

Sources: http://www.fbi.gov/hq/cjisd/takingfps.html