Visible fingerprints, also called patent fingerprints, are those where the ridges are transferred onto a substance like blood, which, in turn, sticks to another surface, like glass. Plastic fingerprints, also called impressions, are indentations of our ridges left on a moldable substance, like clay or wax.

Visible prints are formed when blood, dirt, ink, paint, etc., is transferred from a finger or thumb to a surface. Patent prints can be found on a wide variety of surfaces: smooth or rough, porous (such as paper, cloth or wood) or nonporous (such as metal, glass or plastic).

Fingerprints left on fabric and other surfaces can leave DNA traces, so it can also help forensic scientists to visualise the best area to target on an item of clothing to recover DNA evidence.”

The fingerprints are made of unique pattern of ridges, each of which contains pores, that are linked to sweat glands beneath the skin. All these ridges of fingerprints form a pattern called as arches, loops and whorls. The loops start from one side and exit on the other side.

Loop

From top left to bottom right: loop, double loop, central pocket loop, plain whorl, plain arch, and tented arch.

Fingerprints have three basic ridge patterns: “arch”, “loop” and “whorl”.

Loop fingerprints are the most common type of prints and are found in 60 to 70 percent of the population. Loop prints recurve upon themselves forming a loop shape….Patterns of Loop Fingerprints

• Radial loop.
• Ulnar loop.
• Central pocket loop.

There are four groups of whorls: plain (concentric circles), central pocket loop (a loop with a whorl at the end), double loop (two loops that create an S-like pattern) and accidental loop (irregular shaped).

Fingerprints are skin patterns on the ends of your fingers and thumbs. We always leave fingerprints marks even if we cannot see them! That’s because our skin produces sweat and oil. As a matter of fact, when we pick or touch an object, we leave behind our fingerprints.

6 months old

Use a soft washcloth or feather duster to carefully wipe away any dust from the glass doors. Then, use a microfibre cloth soaked in warm soapy water to remove the fingerprints. Or, use a white vinegar solution (1/4 cup mixed with one gallon of water).

Sir Francis Galton

Francis Galton and Fingerprints

PDF	1888	‘Personal identification and description.’
PDF	1896	Prints of Scars.
PDF	1899	‘Finger prints of young children.’
PDF	1902	‘Finger print evidence.’
PDF	1905	[Review of] Guide to Finger Print Identification, Henry Faulds

Fingerprints are classified into five categories: arch, tented arch, left loop, right loop and whorl.

PRIMARY – The primary classification is obtained through the summation of the value of the whorl type patterns as they appear in the various fingers: Even numbered fingers (2, 4, 6, 8 and 10), being used as the numerator and odd numbered fingers (1, 3, 5, 7 and 9), as the denominator.

Primary Fingerprint Classifications come in the form of a fraction, such as 1/13, 23/2, etc. The numerator and denominator of the fraction are arrived at by adding values associated with each of the 10 fingers.

In biometrics and fingerprint scanning, minutiae refers to specific plot points on a fingerprint. This includes characteristics such as ridge bifurcation or a ridge ending on a fingerprint.

Minutia points are detected by locating the end points and bifurcation points on the thinned ridge skeleton based on the number of neighboring pixels. The end points are selected if they have a single neighbor and the bifurcation points are selected if they have more than two neighbors.

A good quality fingerprint typically contains about 40–100 minutiae.

Fingerprints are generally considered to be a form of class evidence. It is necessary to obtain a full print from a suspect in order to compare his fingerprint with a fingerprint found at the crime scene.

Class evidence consists of substances such as blood and hair, which can be used to place an individual in a general class but cannot be used to identify an individual. For example, blood typing can be used to establish whether someone has A, B, AB, or O blood, but cannot point to a person.

There are two types of evidence — direct and circumstantial. Direct evidence usually is that which speaks for itself: eyewitness accounts, a confession, or a weapon.

Examples of class evidence include blood type, fibers, and paint. Individual Characteristics are properties of physical evidence that can be attributed to a common source with a high degree of certainty. Examples of individual evidence include anything that contains nuclear DNA, toolmarks, and fingerprints.