If you have ever watched an episode of a crime procedural or followed any true crime cases, you are likely familiar with the use of fingerprints to identify people. Every person on earth has unique fingerprints that can be used to trace their movements and identify their presence. Fingerprints are an invaluable tool that helps law enforcement officials solve crimes and convict criminals in court.
But have you ever realised that fingerprints also make lovely mementoes? After all, who doesn’t love the tiny fingerprints (or footprints) of their baby? Or even the beautiful prints from their cat or dog? Fingerprint keepsakes are also perfect as a romantic gesture – they are one in a million (or one in 64 billion, to be exact).
Have you ever wanted to learn more about this fascinating topic? We’ve compiled a guide to everything you need to know about fingerprints.
What Are Fingerprints?
The pressure placed on a foetus’s developing fingers in the womb forms their individual fingerprints. Each of your fingertips is embedded with tiny valleys, ridges, and whorls (collectively called friction ridges) that are utterly unique to your body. The friction ridges include pores that secrete sweat and oils and therefore leave behind residue.
There is less than a one in 64 billion chance that you will have the same fingerprints as another person – they truly unique! They are more individual to you than even your DNA sequences.
While you also have similar ridged areas on your hands and feet, fingerprints are the most popular for identification and solving crimes. That is because we tend to touch everything with our fingers, and we, therefore, leave many prints behind on the surfaces we encounter. As a biometric characteristic, they are easy to store and analyse.
What Are the Different Types of Fingerprints?
There are eight common fingerprint patterns that investigators use to identify people and solve crimes.
Nearly 70% of all fingerprints analysed include loops, which are ridges turned backwards and that do not twist.
- Radial loops
Named for the radius bone that connects to the thumb, radial loops flow in the direction of the radius. They are quite uncommon and are usually found on the index finger.
- Ulnar loops
Ulnar loops are named for the ulna bone in the forearm – they flow down towards the same side as the little finger.
Double-loop fingerprints have a pattern with two distinct shoulders, two deltas, and at least one ridge that makes a full circuit.
Whorls are found in around 30% of fingerprints analysed by experts. In a whorl, the ridges turn at least one full circuit.
- Plain whorl
A plain whorl is the most common. It makes a complete circuit with at least two deltas, making them a circular or spiral shape.
- Central pocket loop whorl
Central pocket loop whorls include at least one curving ridge, an obstruction at right angles to the line of flow, and two deltas. It will be circular, spiral, oval, or circular.
- Accidental whorl
Accidental whorls have two distinct patterns that include two or more deltas. Since they do not match the specifics of other whorl categories, they are grouped together in a ‘catch-all’ group.
Arches only occur in around 5% of all fingerprints, making them the rarest category of features. These patterns do not include any downward turns and run continuously from one side of the finger to the other. They do not usually include a delta.
- Plain arch
Plain arches start on one side of the finger, and then cascade upwards, resembling an ocean wave. They are the simplest fingerprints for amateurs to recognise and are often included in children’s science kits.
- Tented arch
The tented arch has smaller up-thrusts in the ridges near the middle of the finger, resulting in tent shapes that are also easy to recognise.
What Is the Process of Fingerprinting?
The scientific term for fingerprinting is dactyloscopy. Today most fingerprinting is done digitally with scanners, but it was traditionally done with an ink pad and paper.
- Ink fingerprinting
To fingerprint someone with an inkpad and paper, you first clean the finger with alcohol to remove sweat and oil. When the finger is dry, roll it in ink from side to side and up and down. Next, roll the finger onto a card, starting with one side of the fingernail and smoothly gliding it to the other. You can also press a finger firmly onto paper for a flat impression, although this is less useful for analysis. Investigators had to map and compare fingerprints manually by eye, which is a time consuming and complicated process.
- Digital fingerprinting
Most fingerprinting today is done with digital scanners that capture the unique patterns. A person places their finger on a silicone or optical reader for a few seconds, and the computer maps the fingerprint and uses this map to search for matches in the database. Most countries have their fingerprint databases and contribute this information to the Interpol (international policing) system.
Law enforcement agents look for two different types of fingerprints at a crime scene. Visible prints are found in blood, dirt, mud, or any other substance that will hold an impression. Latent prints are invisible to the naked eye or can only be seen in a particular light, and are made on glass, plastic, and other hard surfaces. Investigators use tape, lasers, specialised cameras, or dusting powders to see and ‘lift’ them.
What Is the History of Fingerprinting?
People around the world have noticed the distinct patterns on our hands and feet for millennia. In the second millennium BCE, Babylonian officials fingerprinted criminals! They were also used for signatures in ancient Babylon, with kings and officials imprinting their thumbs or fingers in wax to seal contracts. Similarly, in Ancient China, officials used inked fingerprints in court documents, although this may have just been symbolic.
The first documented case of fingerprints being used to solve a crime dates all the way back to Ancient Rome. A bloody palm print found at the scene of a crime was used to convict the killer. His palm was examined for a match, and this evidence was used against him in court.
In the 19th century, an English magistrate called Sir William Herschel pioneered fingerprinting for signing documents, creating a finger register in Jungipoor, India. Soon after, a Scottish physician called Henry Faulds wrote extensive research papers on the potential for fingerprinting, and his seminal paper was published in ‘Nature’ in 1880.
Soon after, Alphonse Bertillon, a French police officer and biometrics researcher, developed a system dubbed the Bertillon System. It used the measurements of criminal’s body parts, including fingerprints, to track and categorise criminals. It was a flawed system, causing Argentinian police officials, including Juan Vucetich, to reject it and search for better solutions. He began to develop his own system and was able to solve a grisly multiple murder in 1891. He called his system comparative dactyloscopy, the term we still use today.
By 1896 the system had gained popularity around the world, and the National Bureau of Criminal Identification was founded in Chicago (later Washington DC).
Do Identical Twins Have the Same Fingerprints?
Identical twins sharing the same fingerprints is a common misconception that likely stems from the fact that they share the same DNA signature. That said, they can be extremely similar, because they are formed under similar conditions in the womb. No two people have ever been found to share the same fingerprints, including identical twins.
Why Is Fingerprint Jewellery So Unique?
When you love someone, you love their individuality. What better memento to celebrate their individuality than their fingerprint? A piece of fingerprint jewellery is as unique as your loved one – you can guarantee that absolutely no one else on earth will have the same wonderful necklace or ring as you. Imagine everything that you love about someone encapsulated in a single fingerprint – it’s perfect.
The study of fingerprints has a long and storied history that helps us to understand the evolution of law enforcement and detective work. Fingerprints have a truly unique nature makes them the perfect keepsake that will remind you of a loved one’s individuality. This is a genuinely fascinating field of study – have we piqued your inner detective?
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O’Connor, A. (2004). The Claim: Identical Twins Have Identical Fingerprints. The New York Times. [online] 2 Nov. Available at https://www.nytimes.com/2004/11/02/health/the-claim-identical-twins-have-identical-fingerprints.html#:~:text=They%20come%20from%20the%20same [Accessed 22 Jul. 2020].
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