FINGERPRINT PATTERN TYPES

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Loop Impression. 

Developed with Cyanoacrylate Fuming, followed by Rhodamine 6G dye stain, and visualized under Forensic Light Source. 

Then digitally enhanced with Adobe Photoshop 

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Tented Arch Impression

Developed with Cyanoacrylate Fuming, followed by Brilliant Yellow dye stain, and visualized under Forensic Light Source. 

Then digitally enhanced with Adobe Photoshop 

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Arch Impression

Developed with Cyanoacrylate Fuming, followed by Rhodamine 6G dye stain, and visualized under Forensic Light Source. 

Then digitally enhanced with Adobe Photoshop 

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Whorl Impression

Developed with Cyanoacrylate Fuming, followed by Ardrox dye stain, and visualized under Forensic Light Source. 

Then digitally enhanced with Adobe Photoshop 

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LOOP

WHORL

TENTED ARCH


 

Arch Pattern
Ridge flow from side to side, with slight rise or arch in the flow. It can be compared to a hill or bridge.  




 

Plain Language Description of the Pattern Types

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Tented Arch
Ridge flow from side to side, with rise or arch in middle, like an Arch, but it also has at least one ridge that is perpendicular beneath.

It can be said to look like a tent pole beneath the arch, or compared to a mountain, in the same way an arch is compared to a hill. 
 

 

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Loop Pattern
Ridge flow starts on one side, and loops back around the middle, to finish on the same side the ridge began. It may begin and end on the left or right, but if it is an Ulnar or Radial loop will depend what hand it is on.  If it flows to and from the little finger side, it's an Ulnar loop, if it flows to and from the thumb side, it's a Radial loop.

Even if only one ridge loops back to the same side it came from, it is a loop pattern.

(note: if it has two loops, it's a whorl) 

 

Plain
Whorl

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Whorl Pattern
This is the catch all.  If it doesn't fit into the first three, or if it has aspects of two others, it is called a whorl.

This is the most varied pattern type.  

Note: old school curriculums referred to a composite pattern, which is an accidental whorl pattern now
(has been for a while).

There are several types of Whorl Pattern Fingerprints:

Central Pocket Loop Whorl

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Double Loop
Whorl

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Plain
Whorl

Accidental
Whorl

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How Do You Find Fingerprints (Friction Ridge Impressions)?

Fingerprints can be found on a wide variety of surfaces, many of which may surprise you, using a wide variety of methods during a forensic investigation. 

 

However, the key factors to determine how they may be found depend on two main things. 

1. What is the substrate (surface the impression is on); and

2. What is the matrix (what is the fingerprint made up of). 

 

These two factors will help determine what development process may provide the best chance of developing the impression. At the end of the day it is all about creating a contrast between the substrate and the matrix, to allows the impression to visualized. 

To begin, the best type of examination to begin with is the use of light.  Both white light at varying angles (oblique lighting), and the use of forensic light source and filters.

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What Is A Fingerprint

A fingerprint is made up of sweat pores aligned in a row.  Each row containing multiple individual pores, referred to as ridge units.  The believed purpose of such skin, is to increase the friction between the skin and whatever it is in contact with.  As such, what fingerprints are made up of, is friction ridges, and so they are often referred to as friction ridge impressions.  

 

The organization of these ridges are influenced by both genetics, and the environment in which they grow. The random nature of the development process itself, is why they are all unique, and it is a practical impossibility for two to ever be the same! 

Fingerprint Enhancement

To make the small details in a friction ridge impression clear.  We often use digital enhancement tools, to aid our ability to observe all the details in the impression.  

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Impression Analysis

As we examine an impression, before any comparisons are made.  We must first conduct a thorough analysis of all aspects of the impression, and understand what we observe. 

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Fingerprint Comparison

After the discovery, documentation, enhancement, and analysis of a friction ridge impression.  The next step, is to compare it to other known sources, as we try to make an identification.  Although computers can help us narrow the possible sources.  It must be a properly trained examiner to make the comparison. 

 

During the comparison we select a starting point and move from ridge to ridge, as we conduct the comparison. The only way an individualization can be made, is if it is the same throughout, and any slight differences can be explained!  

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Want to learn more about fingerprints, and what they can provide, in addition to identity!

 

Check out Anatomical Factors

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ARCH