Fingerprint Info
The study of fingerprints is called dermotoglyphics. No two fingerprints are alike, even
in twins. Fingerprints are “silent witnesses”, or physical evidence, at a crime scene. The
pattern on your hands and feet are called friction ridges. It’s these ridges that make
fingerprints. The number, shape, and location of each ridge are what make every person
unique, and they do not change with growth or age. Injuries such as superficial burns,
abrasions, or cuts do not affect the ridge structure, either. Each tiny little ridge has sweat
glands on it that produce sweat and transfer it to the surfaces you touch.
There are three different types of fingerprints: patent, plastic, or latent. Patent prints can
be seen without chemicals or equipment. Fingers that are dirty from blood, paint, or ink
leave patent prints. Sweat and oil can also leave patent prints on glass or metal surfaces.
Plastic fingerprints are molded into soft surfaces, and may be in soap, wet cement, or
wax. Latent prints must be developed with chemicals or equipment before they can be
seen.
The Federal Bureau of Investigation (FBI) recognizes eight different types of fingerprint
patterns: radial loop, ulnar loop, double loop, central pocket loop, plain arch, tented
arch, plain whorl, and accidental. Whorls are usually circular or spiral in shape. Arches
have a mound-like contour, while tented arches have a spike-like or steeple-like
appearance in the center. Loops have concentric hairpin or staple-shaped ridges and
are described as “radial” or “ulnar” to denote their slopes; ulnar loops slope toward
the little finger side of the hand, radial loops toward the thumb.
Loops constitute about 65 percent of the total fingerprint patterns; whorls make up
about 30 percent, and arches and tented arches together account for the other 5
percent. The most common pattern is the ulnar loop.
Fingerprints are classified in a three-way process: by the shapes and contours of
individual patterns, by noting the finger positions of the pattern types, and by relative
size, determined by counting the ridges in loops and by tracing the ridges in whorls. The
information obtained in this way is incorporated in a concise formula, which is known as
the individual’s fingerprint classification.
History of Fingerprinting
Sir Francis Galton suggested the first elementary system for classifying fingerprints
based on grouping the patterns into arches, loops, and whorls. Galton’s system served
