1, in ancient times, it was only recognized by the naked eye. However, because the fingerprint lines are too thin to be recognized by the naked eye, we simply choose to record the lines of the whole hand or foot when pressing the fingerprint.
As early as Qin dynasty, the ancients used seals or fingerprints to verify the integrity of this document. Mainly because the wooden slips at that time were very expensive, and all the important documents recorded in them needed to be kept secret. If you find that the lines of the seal or fingerprint are not completely aligned, you can easily identify whether the file has been opened.
3. The clever ancients still had a way to identify fingerprints. This way, that is, pressing the lines of the whole palm or the lines of ten fingers, sometimes even requires prisoners to print their own soles as symbols representing themselves.
At the beginning, fingerprint identification technology was not applied in handling cases, but in order to take care of most people, because in ancient times, many people had low educational level, and some people could only simply draw a few strokes, write a word, draw a cross or draw a circle.