Finger Print Ink: What are fingerprints? Finger print recognition, Ballistic fingerprinting and fingerprint are impressions or marks made on surfaces of objects by people’s fingertips. Fingerprint ink is used in forensic identification of criminals in crime investigations. Forensic finger prints, FBI finger printing, finger printing kits, finger printing card, ink finger printing, finger printing card and safe finger print can all be purchased from forensic supplies store.