Fingerprints

The sense of touch is so important to us as human beings. It helps us with such important things as to feel our way around in the dark, to feel our clothing and to enjoy our pets. Many of the functions that our fingers do for us are mundane and rudimentary activities that we take for granted every day.

One of these that is not often taken for granted is to implicate. Depending on which side of the law you are, your fingerprint can save or convict you. Fingerprinting for the purpose of forensic investigation has been in use for a relatively short period of time compared to its impact on crime.

Purpose of Fingerprints

A human fingerprint does not change over time and is unique to each individual. This fact alone makes it almost as vital to crime fighting as DNA analysis. When fingerprints are analyzed forensically they are looked at for the purposes of detection of drug use, tobacco use and for criminal behavior.

History of Fingerprints

It was discovered in the middle of the 18th century that fingerprints were unique to each person. As early as the 1930’s criminal investigators found latent prints in the insides of the very gloves used to protect the criminal’s hands. The technique of fingerprinting is relatively standard and straightforward in respects to a lot of other crime solving techniques.

One of the more recent developments in the field of fingerprinting is the use of the Scanning Kelvin Probe, a non-contact scientific device which scans the properties of materials. There has also been the recent development of a technique which treats the fingerprint with gold nanoparticles leading to the detection of illicit and prescription drug use, tobacco products and even coffee.

Currently, one of the biggest problems with fingerprinting is at the site of the crime. A decision must be made as to whether a DNA analysis swab must be done or a fingerprint dusting. Once a swab for DNA is done, it destroys the fingerprint. Prior to the discovery of DNA and its importance to forensics, the justice system had no such problem.

Science Behind Fingerprints

The palmar surface of the skin on a human being has something called papillary ridges. Oil and water combined with these ridges make up the fingerprint. Since it is made up of the oils or sebaceous fluids gathered from touching ones face, it is able to remain on the surface that is touched.

Over ninety percent of the fingerprint is water secreted from the skin which eventually disappears. The science behind fingerprinting ranges from the application of fine powders that act as the developer and adhere to the deposits from the fingertip to 3D visualization by the use of infrared lasers.

It is known in the fingerprinting community that there are hundreds of techniques for detection. Some of the more advance and technical methods are ninhydrin and vacuum metal deposition. With metal deposition, gold and zinc is deposited and is able to detect fat layers within one molecule. There are also ethyl cyanoacrylate polymerisation which uses water based catalysis and polymer growth.

There are a lot of critics of the use of fingerprinting techniques and testing, but the practice has remained quite popular among the investigative community. Forensically speaking, the fingerprint is as important to the criminal profile as the mugshot.

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