SCIENCE OF FINGERPRINTING.

THE SCIENCE OF FINGER-PRINTING.

The 21st century has witnessed tremendous change in

the field of forensic science including Fingerprinting.

Fingerprints afford an infallible means of personal identification,

because the ridge arrangement on every finger of every human being

is unique and does not alter with growth or age.

Fingerprints serve to reveal an individual's true identity despite

 personal denial, assumed names, or changes in personal appearance

resulting from age, disease, plastic surgery, or accident.

Fingerprints are classified by the shape and contour of individual

 pattern, by noting the finger position of the pattern type, 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 the individual's fingerprint classification.

United States recognizes seven different types of patterns, radial 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 contour,

while tented arches have a spike or steeple appearance in the center.

 Loops have concentric hairpin or staple-shaped ridges and are described as

radial loops slope toward the little finger side of the hand.

Latent fingerprinting involve locating, preserving, and identifying impression

 left by a culprit in the course of committing a crime. In latent fingerprints,

 the ridge structure is reproduced from sweat, oily secretions, or other

substances naturally present on the culprit's fingers. Most latent prints are

colorless and must therefore be developed, or made visible,

before they can be preserved and compared.

This is done by brushing them with various gray or black powders

containing chalk or lampblack combined with other agents.

The latent impressions are preserved as evidence either by photography

or by lifting powdered prints on the adhesive surfaces of tape.

Other Fingerprinting techniques include the use of a sound spectrograph,

a device that depicts graphically the frequency, duration, and intensity,

to produce voice-graphs, or voice prints, and the use of  DNA fingerprinting,

 an analysis of those regions of DNA that vary among individuals,

 to identify physical evidence blood, semen, hair, etc. as belonging to a suspect.

The latter test has been used in paternity testing as well as in forensics.