(Research) Fingerprints are classified into three kinds. Whirls, loops, and ridges are the three varieties of fingerprints. The loop was determined to be the most prevalent, accounting for 60 to 65 percent of the total. The next most common type of fingerprint was the whorl, which accounts for about 10 percent of all prints. Last but not least, the ridge is the rarest type of fingerprint, making up only about 25 percent of all prints.
Fingerprint classification is based on the morphology of the skin at the point where it contacts a surface. The three main types of fingerprints are shown below. It is important to understand that these are general descriptions of what will usually happen with any individual print. Some fingerprints may contain features of more than one kind or may even change over time.
Fingerprint templates are used by police departments across the country to identify individuals who have been arrested but not charged with a crime. A template is a plastic or metal plate with indentations that represent different parts of a fingerprint. When a fingerprint is placed on the template, the corresponding points of contact reveal information about the pattern of skin growth around those points. This allows an expert to estimate how long ago the print was made.
Fingerprinting is also used by criminal investigators to help identify people who have been killed.
Fingerprints are classified into three categories: loops, whorts, and arches. Loops are the most prevalent form of fingerprint; on average, loops account for 65 percent of all fingerprints. Whorls account for around 30% of all fingerprints, whereas arches appear just about 5% of the time. Each of them has its own subcategory. For example, a looped pattern is called a "rolled" print; if it's a straight line, then it's an "irregular" print.
Fingerprint classification system was developed in 1941 by Edward H. Adler. He divided fingerprints into six regions based on overall appearance and structure. These regions are known as "focal points." The two central regions are referred to as "corresponding prints," because they contain a matching pattern of ridges and valleys. The other four regions are "free-standing prints" because they do not correspond to any part of the hand. They include: ulnar fovea, radial fovea, hypothenar area, and dorsal surface of finger I.
These include: ulnar border, radial border, hypothenar border, and first web space of the hand. A non-corresponding print may or may not have a counterpart on the opposite hand. For example, there is no region on the ulnar side of the hand that matches up with the hypothenar area on the radial side.
How frequently does each occur? Loop fingerprints, which are found in approximately 60–65 percent of the population, whorl fingerprints, which are found in approximately 30–35 percent of the population, and arch fingerprints, which are found in approximately 5 percent of the population, are the three types of fingerprints found in the human population. Loop, whorl, and arch fingerprints appear with age; people get better at copying them over time.
Loop fingerprints are the most common type of fingerprint found in the general population. They are characterized by a series of loops and coils that usually follow a curve or arc when viewed from the side. The pattern is caused by elasticity of skin tissue when pressed into something hard, such as glass. The term "loop" also describes the shape of some foreign objects that become embedded in skin tissue, such as jewelry, needles, and wire.
Whorl fingerprints are characterized by a series of curves and coils that wrap around an axis (such as the center line of a palm) but do not cross it. These patterns result from elasticity of skin tissue in areas where fingers join together, such as at the wrist or on the back of the hand. Whorl patterns may be simple or complex. A simple whorl consists only of curved lines without any crossings or breaks. A complex whorl has several branches or loops that intersect one another at various angles.
Fingerprints are classified into three types: latent, patent, and plastic. Sweat and oil on the skin's surface combine to form latent fingerprints. When you press your finger against a surface, sweat glands in your body produce moisture that is absorbed by the surface being touched. The moisture leaves a print that can be used for identification purposes.
If you have ever gone to the bathroom before entering a room where blood has been spilled, then you have probably washed off any blood that was on your hands. This is because human blood contains sodium acetate, which causes skin to dry out quickly. After washing my hands in water with some soap, if I walk through the same room minutes later, the blood will have left a latent print on the wall or door handle that can be used for identification.
You can also leave latent prints behind at other times, such as when you use a phone book or dictionary to check names or numbers while talking on the phone. The time between touching two objects is called the touch-time. If you don't wash your hands right away, the print may become invisible after several hours or days.
Latent prints are invisible until treated with a special solution.
Loop. The most prevalent form of fingerprint is the loop. The ridges connect to create elongated loops. Some people have double-loop fingerprints, which form a curving S shape. Other patterns can also be found, such as arches and whorls.
The second most common type of fingerprint is the spot. These areas are flat and do not curve like the loops do. People with spotty fingerprints often have more spotty hands.
Third most common is the line. These lines run across the finger in an irregular pattern. They can be single or multiple lines. People with single line prints usually have only one line running across their finger. Those with multiple lines sometimes are missing pieces of skin where lines cross over each other.
Fingerprints change over time due to growth and aging. This is normal; it does not mean anything abnormal about your health. A doctor may ask to see your fingerprints if she wants to know how old you are based on their pattern. For example, if your fingers are thin and long compared to the rest of your hand, then you are likely a male and probably older than 25 years old.
Your fingerprints are unique to every person and cannot be used to identify someone else. However, similar patterns tend to come up again and again for the same person.
Plastic fingerprints are three-dimensional impressions created by pressing your fingertips against freshly applied paint, wax, soap, or tar. They can be used to identify someone who has touched something with these fingers.
Latent fingerprints are invisible to the eye but are still visible light when you shine a strong light onto them. They can be seen in dust under artificial lights inside police stations and labs. Latent fingerprints are useful because they show which objects have been handled by crime scene photos.
Inspecting and analyzing latent fingerprints is called "laboratory work." Police departments usually have laboratories where this work is done. Laboratory technicians study the pattern of ridges (nooks) on the finger surfaces and compare them to records of previous cases. This allows them to make an identification if they come across another case that is similar to yours.
The best time to take a print is immediately after touching something with your finger. The moisture from your hand will help the ink spread out over more of the finger surface. Don't wash your hands right away though, or you'll remove any evidence that may have remained.
Patents are visible prints left by anyone who has touched something with their finger. These prints are often found at crime scenes.