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How Long Do Fingerprints Last and Fingerprint Patterns latent patent plastic

Fingerprint Pattern Overview

Crime scene investigators will take a variety of prints from the scene such as transfer prints (Latent, Patent, and plastic) and Fragmentary prints (incomplete impressions that may only show portions of the print.) Crime scene investigators will use what are called exemplar fingerprints, which are a collection of known individuals to compare to the fingerprints found at the crime scene. These fingerprints are typically obtained during arrests, job applications, and identification purposes which are sent into a database. The prints found at the crime scene can also be used to be compared to a person of interest who are not already in the database. Elimination prints are obtained to rule our individuals who were are the crime scene (before, during , or after) but are not suspects. For example, a helpful witness who entered a house during a home invasion, or an innocent roommate. These prints help narrow down the fingerprints of the suspects as they can rule out prints that are reasonably left at the crime scene.

Do Twins Have Matching Fingerprints?

Although twins will share DNA they do not share the same fingerprints. No two fingerprints are alike and are a strong way of identifying and connecting individuals to a crime scene.

How long do Fingerprint last?

How Long Do Fingerprints Last and Fingerprint Patterns oils
How long do Fingerprint last?​

In theory fingerprints left by an individual can last forever depending on a multitude of circumstances including the substance the print was left on, the weather, dust, debris, or if anything touches the print or moves the object. This is why you will still see detectives and forensic technicians process a crime scene years after, as valid and usable fingerprints may be developed. Fingerprints are not normally left with a set of perfect circumstances, so it is important that they are processed as quickly as possible. A fingerprint left outside in the pouring rain will likely disappear as opposed to one found in an untouched basement a month later. There have been several advancements in exposing fingerprints long after they have been left and have been used to successfully convict criminals.

What Are the Three Different Types of Fingerprint Pattern Classifications

How Long Do Fingerprints Last and Fingerprint Patterns arch loops whorls

There are three main types of fingerprint pattern classifications. These identifiers are used to identify and trace suspects, victims, involved parties and witnesses back to the scene of a crime.  The three main types of fingerprints are based off their obvious ridge patterns and are Arches, Loops, and Whorls. Keep in mind that each fingerprint can have a combination of one (1) to all three (3) of these patterns.

Fingerprint Patterns and Characteristics

Arch Pattern fingerprints

How Long Do Fingerprints Last and Fingerprint Patterns whorls arch loops
Arch Pattern fingerprints

Arches are the simplest type of fingerprint patterns. As you can see above, they form a wave-like pattern that forms a gentle arch. The height, width, pattern, and slope of the arch will be different and unique to each individual. Unlike the Whorl and Loop fingerprints, they do not have any deltas (A delta is a triangular ridge pattern that divides into separate lines.) The arch fingerprint is the least common of the fingerprint classifications. We can also further divide the arch fingerprint into two subcategories, one with plain arches and the other with tented arches. This secondary classification depends on the presence and angle of the raised center. Approximately 5% of the population have arch patterned Fingerprints and is the most rare.

Plain Arch Pattern

A plain arch flows smoothly from one side of your finger to the other, which will form what appears to be an effortless and unbroken arch pattern.

Tented Arch Pattern

Unlike the plain arch these fingerprints show a sharper rise in the center which gives it the look of a tent-like structure with a more pronounced angle at the top of the “tent”. The Tented Arch is the least common of the two arch fingerprints.

Loop Pattern Fingerprint

How Long Do Fingerprints Last and Fingerprint Patterns whorls arch loops
Loop Pattern fingerprints

Loop fingerprints are the most common type of fingerprint patterns estimating to make up 60-65% of all fingerprints. Loop fingerprints will have at least one ridge that will enter from one side of the finger, recurve around and then exit from that same side of the finger. Loop fingerprint individual characteristics can be distinguished through the position, shape and position of the delta, ridge count and pattern. The directions of the loops can also help identify movement and/or orientation of the finger when the print was deposited. The Loop fingerprints will have one or more deltas that are divided into two subcategories based on their direction.

Ulnar Loops

Ulnar loops are when the ridges flow in a pattern towards the ulnar (little or pinky finger) side of the hand. Normally the delta point is located on or near the side of the thumb.

Radial Loops

Radial loops are when the ridges flow in a pattern towards the radial (Thumb) side of the hand. Like ulnar loops the delta point is often located on or near the side of the thumb.

Whorl Pattern Fingerprints

How Long Do Fingerprints Last and Fingerprint Patterns whorls arch loops
Whorl Pattern Fingerprints

Whorl Fingerprints are characterized through their circular or spiral ridge patterns. They contain one or more ridges that will make a complete circuit with two deltas present.  Whorl fingerprint individual characteristics can be distinguished through the position, number of ridges encircling the pattern, location and shape of the delta points, and overall flow of the print. Whorl prints are considered more complex than arch or loop fingerprints as they may present intricate ridge formations. Approximately 25% of the population has Whole fingerprint patterns. There are four (4) subcategories of whorl fingerprints based on their specific ridge configurations.

Plain Whorls

The ridges will form a complete circuit and spiral around the central point with at least one delta point within the pattern.

Central Pocket Loop

The central pocket loop resembles the plain whorls however, has an added loop or pocket within the central area of the pattern.

Double Loops

The double loop has two separate loop formations with separate delta points

Accidental Whorls

The accident whorl does not fit smoothly into the other three subcategories. Accidental whorls will contain a combination of two or more patterns or separate loop formations.

What are the Three Types of Fingerprint Classifications?

The three types of fingerprint classifications are Latent, Patent, and plastic prints. Although these prints have their differences, they all focus on identifying the patterns matching an individual. Fingerprints are a powerful evidence that can lead to the apprehension and conviction of a suspect.

Latent Fingerprints

Although Latent fingerprints are invisible to the naked eye, law enforcement officers and investigators can sometimes see smudges on a glass window, moved dust or some other indication that a viable fingerprint is present. Anything that appears moved or touched would be a prime target for laten prints and will be a likely target of forensic investigators. One of the major obstacles of latent fingerprints is they are invisible. Since they are hard to find they can be easily destroyed if stepped on or touched. Below are the most common ways of revealing latent prints.

Powdering Latent Fingerprints

Crime scene investigators or technitions use a fine powder such as aluminum or graphite powder to reveal the fingerprint. This process works because the powder will only adhere to the residue (oils, sweat, other substance) left by fingerprints and dust off the other areas. This will hopefully reveal a viable print or partial print, where the crime scene investigators can send it into the lab for further analysis. Before using some clear adhesive tape or other approved method of collecting the fingerprint, the crime scene investigator will often take multiple photos of the print and the location. Technology is becoming more and more advanced as the initial photograph of the fingerprint can be sent into a large databased and analysis by the thousands. Powdering is the easiest and most common way of collecting fingerprints.

How to dust and lift a fingerprint

Exposing Latent Fingerprint with Chemical Reagents

There are certain chemicals that will react with the components of latent prints, helping them become visible. Some of the examples are ninhydrin, cyanoacrylate (Superglue) fuming, and iodine fuming.

Dry Stains Technique for Latent Prints

These stains are gentian violet or basic yellow 40, which can help selectively color the components of the laten print, making them visible against the background.

Revealing Latent Prints With Laser or Alternating light Sources

These sources emit light at a specific wavelength that causes the prints to absorb light (become visible) compared to the surrounding surface. This makes the print almost glow and fluorescent in color.

Patent Fingerprints

Patent prints are apparently visible to the naked eye as they are an imprint of a handprint or fingerprint that were left using a substance such as blood, dust, dirt, or ink. Patent Fingerprints are easily identifiable, so crime scene investigators can take an initial picture and process the print with an approved clear adhesive tape to keep the fingerprint intact. Some substances such as a condiment like mustard, may be difficult to fully keep intact in its liquid form so the initial picture and waiting for it to completely dry is extremely important in matching the print.

Plastic Fingerprints

Plastic fingerprints are less common than the other two but provide more information about the matching finger. Plastic fingerprints are impressions left in soft materials such as putty, wax, or clay. These impressions can create a more 3D view of the finger with valuable information you may not get from a latent or patent print.

Conclusion: How Long Do Fingerprints Last and Fingerprint Patterns

Fingerprint evidence is exceptionally valuable to a case as it can demonstrate that a suspect was at a crime scene or near a location. Just the presence of a valid fingerprint at a crime scene can lead to a connection, thus a potential conviction. Although Fingerprints are important, there may be an easily explainable reason as to why a suspect’s fingerprint was in a certain location. For example, if a husband killed his wife during an argument in her car, of course there is going to be his fingerprints inside the vehicle. The husband and defense team can explain that he has been in her car before and/or frequently drives it. Alternatively, in the above scenario, the wife was murdered by a random male and there was a fingerprint located on the inside glass window of the victim’s vehicle. That would be hard evidence against the suspect as they would have no reasonable answer as to why his fingerprints were located in the inside of the victims door window.

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By Branden

Branden is a Police Lieutenant who has investigated numerous crimes. He has written and executed multiple search warrants, conducted various protective sweeps, pat frisks and exit orders. He has been involved in numerous police vehicle chases, fights, disturbances, foot pursuits, suspect/hostage negotiations and felony stops. He is trained with an assortment of weapons. He has spoken with countless victims, witnesses and suspects and is using his experience to better protect our communities and loved ones by sharing his knowledge through his writings.

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