Fingerprints are far from foolproof. When it comes to evidence, when it comes to self-locking and unlocking devices, when it comes to having prints taken for official purposes… and everything else fingerprints are used for in this day and age, a dirty or fake fingerprint can throw off the whole process.
But there’s a kind of secondary fingerprint that’s a lot more reliable. Turns out, there’s a fingerprint of sorts just beneath your skin. It matches the superficial fingerprint, and serves as something like the master blueprint that makes the fingerprint with which you and I are familiar. This fingerprint-under-the-fingerprint won’t fall victim to dirty hands or old age, and, so far anyway, it can’t be faked. The Wall Street Journal explains it well:
“…A fingerprint matching the one on the surface of the skin lurks about a half millimeter below the surface, in an area rich with other potential identifying characteristics such as sweat pores and tiny blood vessels.”
A specialized infrared camera is able to gather the information held in this fingerprint-beneath-the-skin. It’s very expensive, so we’re not going to find this technology on iPhones anytime soon, but it’s interesting to know that the technology exists.