What is Finger Print Analysis?
When humans come in contact with an object or touch it, they leave a proof behind in the form fingerprints – friction ridges of a human finger. Oil and sweat gets collected on these ridges and is transferred to objects, thus leaving a duplicate of the fingerprint pattern. Sometimes, the secretions may seep into an absorbent surface such as a paper, leaving a slight blot. And, sometimes if a finger makes contact with a liquid or a thick substance, such as ink or blood, it may leave a visible print behind. Human fingers, toes, palms and foot soles are naturally covered with friction ridges that help a person in gripping objects and the ground. These ridges are also connected to our nerves, so the individual feels even if it has a slightest of pressure against the ridge. These ridges create the patterns of the fingerprints. These fingerprint patterns are formed in the womb and remain in the body till death. They hardly change unless and until there is some kind of injury, mutation or external change. Our fingerprints have tiny lines of concentric ridges. The general forms these ridges take are loops, accidental, whorls and arches. There are many print records that are organized into these categories for easy reference during fingerprint analysis.
The ridges make distinctive fingerprints that are based on minute variations in their patterns. The small differences are called finer points or minutiae. Common finer points include ridge endings; ridge splits culled bifurcations and crossovers that connect two ridges. Other minutiae include lakes, islands, and dots. Lakes are open places with a single ridge. Islands are small ridges, and dots are minute ridges that are nearly round. The fact that fingerprints remain unchanged almost throughout life is one reason that makes fingerprint analysis successful in identifying individuals from their prints. Every pattern is different and unique and not even one finger has the same print. Although no study has confirmed that all fingerprints are exclusive in all the years of records, no two have ever been found to be totally matching. Everyone’s finger pattern is exclusive, which is why they are used widely by forensics to identify individuals.
Basic Patterns & Understanding of Fingerprints
Fingerprints are little ridges on the end of human fingers and thumb. These ridges are arranged in a pattern of spirals and loops. Nature made these such that we can grip and hold on to things. The surface prevents things from getting slipped and slide as it can happen naturally especially when our hands are wet or sweaty. In the early 1900s, people started to realize that fingerprints were unique – no two people have exactly the same fingerprint patterns. Fingerprint patterns are genetic but can never be the same. Even in the cases of identical twins, the patterns differ slightly. Sir Francis Galton was the first one to utilize this knowledge in solving criminal casesat Scotland Yard in England. He introduced the technique of comparing prints found at a crime scene with those of a suspect. Much of his work was based on theobservations of Sir Edmund Henry, and together their approach was called the Galton-Henry System. In the year 1904, Juan Vucetich, published a paper titled, Comparative Fingerprints. His technique is still used widely in Spanish speaking countries. All these systems are mainly similar. Edmund Henry realized that fingerprintscan be described as having patterns of arches, loops, accidental or whorls. These shapes and contours were later upgraded to eight basic patterns, which are still used by the FBI today.
Some of the fingerprint patterns are given below:
In arches, the finger ridges run constantly from one side of the finger to the other with no re-curving. There are two groups that further define the arch pattern.
Plain Arch – This pattern has a uniformity of flow to it. Starts from one side of a finger, and then ridge move upward a bit, almost resembling a wave out in the ocean. The plain arch then continues the journey along the finger to the other side. The plain arch is most simple of the fingerprint patterns to tell the difference.
Tented Arch – This pattern is same like the plain arch and it begins on one side of the finger and flows out in a related pattern to the other side. Though, the disparity in the tented arch is in the ridges in the center that are not constant as in the case of the plain arch. The ridges, which connect each other in the center, join and push upward, giving the idea of a pitched tent.
In loops, the ridges turn backwards but do not curl. This backward turn or loop is distinguished by how the loop flows in the hand and how it does not flow on the card on which the impression is taken. The mark on the fingerprint card is same as of the reverse image that we see when we see ourselves in the mirror.The two sub- groups that Henry recognized in this category are:
Radial Loop – These loops flow to the radius bone of the hand.
Ulnar Loop -These that flow when the descending slope of the loop is from the direction of the thumb toward the little finger of the hand.
Whorls have patterns in which there are two or more deltas and there also exist a re-curve foregoing each delta. The sub-groups of whorls are:
- Targeted Whorl
- Spiral Whorl
- Elongated Whorl
- Peacock’s Eye
- Composite Whorl
- Double Loop Whorl
- Imploding Whorl