Fingerprints can be developed on objects that have been in water. There are very few surfaces on which a print cannot be developed. Computers have revolutionized the techniques used to match fingerprints. It could take weeks, sometimes months to compare a suspect fingerprint to a department's print files. The advent of digital technology has changed all of that.
Prints can be image scanned directly into a computer, doing away with ink and fingerprint cards.
Prints can be compared at a rate of 400,000 per second. You couldn't do that in your lifetime. Automated Fingerprint Identification System. Departments will input all the prints from arrests and all of the print cards they already have on file to create an historical record. They also input all of the prints from any unsolved crimes, in the hope that a hit might come up from a routine arrest.