How Does Fingerprinting Work?

Fingerprinting uses digital scanning technology to take an imprint of a person's fingerprints. The most common form of fingerprinting is rolled fingerprints. This type of fingerprinting requires the person to thoroughly clean his finger and roll it on an ink pad before rolling it on a prepared card.

When fingerprinted, a person uses alcohol to clean the fingerprint area. The finger is placed on an ink pad and rolled to ensure ink covers the entire area. Then the person rolls his finger across a prepared card, usually at a 45-degree angle, leaving a fingerprint.

More and more, government agencies and businesses use digital fingerprint scanners. These scanners do not require ink. A person places his finger on an optical or silicon fingerprint reader and the reader converts the information into a data pattern. The computer can map the fingerprint to help identify a person.

Law enforcement and other agencies use fingerprints as a way of identifying a person. They use the scanned fingerprints in a database that compares them to others. No two people have the same fingerprints. Although using fingerprints as a method of identification since ancient times, law enforcement did not begin using it as a way of identifying criminals until the 19th century.