Fingerprints

Fingerprinting has always been used, but it wasn’t until modern times that it was used for identification. In ancient Persia fingerprints were used to sign documents and were continued to be used as a way for singing contracts for many years. It wasn’t until 1880 that the importance of fingerprints for identification was realized by Dr. Henry Faulds. Even with Faulds research the Bertillon method of identification more popular. The Bertillon method of identification was involved by Alphonse Bertillon and involved taking the measurements of a person to identify them. Finger prints were used as a secondary means of identification until a man was wrongly jailed because he shared similar measurements with his twin brother. From that point on fingerprints were used as a primary means of identification. In 1892 Joan Vucetich was the first to use fingerprints in a criminal investigation identifying a murderer. Through out the years finger printing became more common being adopted by US prisons, the Army, the Navy and the Marines. As finger printing spread hundreds of millions fingerprint cards were made around the world. To keep track of criminals and citizens alike automated systems, such as AFIS (1946), were created around the world. The FBI posseses the largest AFIS system and all states will posses their own AFIS systems. Today fingerprinting is an invaluable in the fight against criminals world wide.

There three types of fingerprints, direct, latent and plastic. A direct fingerprint is visible because it is usually left in one of these mediums: grease, dirt, blood, ink, or paint and does not require dusting before lifting the print.

A latent print is not visible to the naked eye and is usually left on either dark or glass surfaces. To lift a latent print on glass a darker powder, such as black carbon, is required when dusting to see the contrast before lifting. On a dark surface a lighter dusting powder, such as aluminum powder, is required to see the contrast before lifting.

Finally plastic prints are ridge impressions and impressed into a soft medium such as wax, putty, soap, or dust.

Besides darker and lighter powders like black carbon powder and aluminum powder there are other techniques and chemicals to lift prints, such as magnetic-sensitive powders, fluorescent powders, and the iodine fuming process. The different types of prints and different locations of the prints require different chemicals and techniques. For latent prints iodine fuming and fluorescent powders are most effective. Powders should be used when the surface is a dark hard surface lighter powders should be used and for glass surfaces darker powders should be used. For softer surfaces chemicals should be used.

(These are the eight types of finger prints).


Sources:
http://www.bxscience.edu/publications/forensics/articles/fingerprinting/f-fing03.htm http://odec.ca/projects/2004/fren4j0/public_html/types_prints.htm http://www.onin.com/fp/fphistory.html