2. Types of Fingerprints

There are three kinds of fingerprints: Patent, latent, and impressed

1. Patent prints which are also known as visible prints are able to be seen with the naked eye. They can be when blood, dirt, ink or grease on the finger come into contact with a smooth surface and leave a friction ridge impression that is visible without development.

2. Latent prints are not apparent to the naked eye. They are formed from the sweat from sebaceous glands on the body or water, salt, amino acids and oils contained in sweat. The sweat and fluids create prints that must be developed before they can be seen or photographed. They can be made sufficiently visible by dusting, fuming or chemical reagents.

3. Impressed prints are also called plastic prints and are left in soft pliable surfaces, such as clay, wax, paint or another surface that will take the impression. They are visible and can be viewed or photographed without development.

http://odec.ca/projects/2004/fren4j0/public_html/types_prints.htm