Saturday, August 29, 2009

Procedures for Collecting/Lifting Fingerprints

After finding a fingerprint (simply by seeing it or exposing it with a UV ray) dust the print off with powder (white powder for dark surfaces, black powder for light surfaces/glass). Next, place specialized tape over the print to remove the print. Another procedure is, if the print is visible, to simply photograph the print.

Basic Shapes/Patterns of Fingerprints

Techniques/Chemicals Used to Develop Fingerprints

With any surface, the first technique to use for finding fingerprints is optical techniques. Optical techniques are when different types of lighting, such as ultraviolet light, is used to expose otherwise invisible prints. On a porous surface, you have to find out whether or not the surface where the print was left was wet. If it was, more than likely the latent fingerprints will not turn up. On dry porous surfaces, DFO, ninhydrin, and metal salt treatment are different technique options. On nonabsorbent surfaces, after finding the fingerprint, put powder (white for dark surfaces, black for light colored/glass surfaces) over the print, then dust the extra powder away to make-out the print.

Thursday, August 27, 2009

Types of Fingerprints

Direct- fingerprints left with another substance (ex: blood, mud, powder, etc.)
Latent- fingerprints not immediately visible
Plastic- when a fingerprint is imprinted on a maleable surface

Monday, August 24, 2009

History of Fingerprinting

Fingerprinting was around in many ancient civilizations. However, it wasn't use for identification. Some cultures used fingerprints as their signatures, and others used them for business transactions.
Identification with fingerprints began around 1686 with Professor Marcello Malpighi. He noticed that fingerprints had ridges, spirals, and loops. In 1823, Professor Jan Evangelista PurkynÄ› published his thesis on 9 fingerprint patterns that he discovered. He claimed that there were different patterns in fingerprints which made up the different prints. The same would be discovered again in 1858 by Sir William James Herschel when the English first began fingerprinting. He used fingerprints for signing contracts. At first he made them use their entire handprint, but later moved to fingertips for printing. After a while he noticed that different person’s fingerprints were not all the same. He, too, noticed that different fingerprints had different patterns on them.

In 1880, Dr. Henry Faulds (credited with the first fingerprint identification) created a way to classify fingerprints. 1882, Gilbert Thompson of the U.S. Geological Survey in New Mexico, used his own thumb print to prevent forgery on a document. In 1882, Alphonse Bertillon devised a system of classification, known as Anthropometry, or the Bertillon System. He used measurements of parts of the body and said that the measurements would only identify one person (different measurements for different people). This method proved invalid when a set of criminal twins were found to have the exact same body measurements

In 1897, the Council of the Governor General of India approved a committee report that fingerprints should be used for classification of criminal records. In 1903 is when the New York State Prison system began the first systematic use of fingerprints in the U.S. for criminals. Through 1905-1908 the U.S. Army, Navy, and Marine Corps began using fingerprints to identify their soldiers. Fingerprints are still used today for identification and, occasionally, signatures.