Do you know how fingerprints work?
If there is a crime scene investigation, what is the first thing your local police check for? The possible fingerprints mistakenly left around by the criminal. Why? Because each of us has these unique sets of prints that our fingers leave, distinguishing us from one another. But what is there in our fingers that makes them unique? Come, let’s find out together.
The uniqueness lies in the composition
Ever thought about what fingerprints are made up of? They are made up of an arrangement of ridges, called friction ridges. Each of these ridges has pores that are connected to the sweat glands under our skin. When we touch or hold a table, glass, plate or anything else during the day, we leave our fingerprints on it because of this sweat. The sweat shows the patterns in the ridges of our fingerprints. These patterns are arches, loops and whorls. The shape, size, number and arrangement of minor details in these patterns are what makes each of our fingerprints unique.
Arches, loops and whorls
So let us first understand what these arches, loops and whorls are. Arches slope up and then down, like narrow mountains. Loops start on one side of your finger, curve up or around and end on the other side. These are mainly of two kinds: Radial loops that slope towards the thumb and lunar loops that slope towards the little finger. Whorls, as the name suggests, form circular or spiral patterns. So, if you look at your fingers you will know what kind of finger patterns you have. At the same time, if you look at the fingers of any of your friends, you will see that they have a very different arrangement of these patterns on their fingers than yours.
Why are fingerprints so crucial?
Fingerprints are a key determinant for forensic experts in any investigation. They are even more unique than human DNA. Two identical twins may have the same DNA, but not the same fingerprints. Surprising, isn’t it? Also, fingerprints don’t change as we age. This means, a person will have the same set of fingerprints the whole of his life unless the deep or ‘basal’ layer of his finger is destroyed or intentionally changed by plastic surgery. Fingerprints are also used for biometrics by governments to keep identity records. You must have used your finger scan to unlock your screen? This technological use of fingerprints is growing in popularity.
Different types of fingerprints
Fingerprints can be broadly divided into three categories -patent, plastic, and latent. Suppose you are writing some notes with an ink pen and it leaves some ink on your finger. What you leave behind after touching a smooth surface with that finger is a patent fingerprint, visible to the naked eye.
Plastic prints are basically impressions that you tend to create on your fingers when you touch something soft like wax or playdoh. They’re also visible to the naked eye.
However, latent prints, are not visible. We tend to leave them on anything we tough.