Forensic Science: Fingerprints

Gap-fill exercise

Fill in all the gaps, then press "Check" to check your answers. Use the "Hint" button to get a free letter if an answer is giving you trouble. You can also click on the "[?]" button to get a clue. Note that you will lose points if you ask for hints or clues!
A fingerprint is an impression of the friction of all or any part of the finger.

Arch Print

Arch Fingerprint

A friction ridge is a raised portion of the .

Fingerprints may be deposited in natural secretions from in friction ridge skin. , oil and grease, can be transferred to the surface of an item when friction ridges come into contact with the surface of the item. Fingerprints may also be made by using black printer's ink transferred from the peaks of friction skin ridges to a smooth surface such as a fingerprint .

The factors which affect friction impressions are many, and include pliability of the skin, the pressure applied, slippage, and the nature of the surface.

Fingerprint is the process of comparing impressions from fingers or palms to determine if the impressions are from a suspect's finger or . The flexibility of friction ridge skin means that no two fingerprints are ever the same.

Whorl Print

Whorl Fingerprint

There are three basic fingerprint patterns: Arch, and Whorl. There are also more complex classification systems that break down patterns to plain arches or arches. Loops may be or ulnar, depending on the side of the hand the tail points towards. Whorls also have classifications including plain whorls, accidental whorls, double whorls, and central pocket loop whorls.

A new technique has been developed to allow fingerprints to be detected on metallic and electrically conductive surfaces without the need to develop the prints first. The technique involves the use of an instrument called a Scanning Kelvin (SKP), which measures the voltage at intervals over the of an object . These measurements can then be mapped to produce an of the fingerprint.