FINGERPRINT PATTERN TYPES
Loop Impression.
Developed with Cyanoacrylate Fuming, followed by Rhodamine 6G dye stain, and visualized under Forensic Light Source.
Then digitally enhanced with Adobe Photoshop
Hover here to see more
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
Hover here to see more
Arch Impression
Developed with Cyanoacrylate Fuming, followed by Rhodamine 6G dye stain, and visualized under Forensic Light Source.
Then digitally enhanced with Adobe Photoshop
Hover here to see more
Whorl Impression
Developed with Cyanoacrylate Fuming, followed by Ardrox dye stain, and visualized under Forensic Light Source.
Then digitally enhanced with Adobe Photoshop
Hover here to see more
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
Tented Arch
Ridge flow from side to side, with rise or arch in middle and at least one perpendicular ridge beneath. It can look like a tent pole beneath the arch, and be compared to a mountain, in the same way an arch is compared to a hill.
Loop Pattern
Ridge flow starts on one side, and loops back in the middle, to finish on the same side the ridge began. It may begin on the left or right, but will end on the same side as it began. Even if only one ridge loops back to the same side it came from, it is a loop pattern.
(note: if there are two loops, it's a whorl pattern.)
Whorl Pattern
This is the catch all. If it doesn't fit into the first three, it is called a whorl. This is the most varied pattern type. Old curriculums often referred to a composite pattern, which is a whorl pattern now (has been for a while).
.jpg)
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.
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 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!
Want to learn more about fingerprints, and what they can provide, in addition to identity!
Check out Anatomical Factors
