Fingerprint Patterns:
Loops (60%-65%)
Arches (30%-35%)
Whorls (5%-10%)
US vs. Bryon C. Mitchell
The admissibility of fingerprint evidence was challenged. The judge upheld fingerprints are admissible because:
1. Human friction ridge patterns are unique and permanent.
2. Human friction ridge skin arrangements are unique and permanent.
Fundamental Principles of Fingerprints:
1. A fingerprint is an Individual Characteristic
2 A fingerprint will remain unchanged during an Individual's Lifetime
3. Fingerprints have ridge characteristics that permit them to be systematically classified.
The two factors fingerprints are controlled by:
1. DNA.
2. Environment in the womb.
Epidermis
Outer portion - the upper or outer layer of the two main layers of cells that make up the skin.
Dermis
Inner skin - the thick layer of living tissue below the epidermis that forms the true skin, containing blood capillaries, nerve endings, sweat glands, hair follicles, and other structures.
Dermal Papillae
Boundary between the Epidermis and Dermis - the shape of the dermal papillae determines the form and patterns of the ridges on the surface skin.
Latent Fingerprints
Invisible to the eye.
Plastic Fingerprints
A reverse image where the valleys look like ridges and the ridges look like valleys.
Visible Fingerprints
A substance is on the finger and then a print is made.
Fingerprint
Is an individual characteristic; no two people have been found with the same exact fingerprint pattern.
Arches
Simplest type of fingerprint that are formed by ridges that enter on one side of the print and exit on the other. No deltas present.
Plain Arch
Ridges enter on one side and exit on the other.
Tented Arch
Ridges enter on one side and exit on the other, has a spike in the center.
Loops
Must have one delta and one or more ridges that enter and leave on the same side.
Radial Loop
Loop opens toward thumb or radius bone on the right hand.
Ulnar Loop
Loop opens toward the little finger or the ulna bone on the right hand.
Whorls
Have one ridge that makes (or tends to make) a complete circuit. They also have at least two deltas.
Plain Whorl
When a line drawn between two deltas bisects part of the central core.
Central Pocket
When a line drawn between two deltas doesn't bisect part of the central core.
Double Loop
Made up of any two loops combined into one print.
Accidental
Contain two or more patterns (not including the plain arch), or does not clearly fall under any of the other categories.
Ridgeology
Is the study of the uniqueness of friction ridge structure their use for personal identification.
A.F.I.S.
Automated Fingerprint Identification System
Minutiae
Points where the ridge structure changes.
Core
Whorl pattern: found in the middle of the spiral.
Loop or Arch pattern: the top region of the innermost loop.
Ending Ridge
A single ridge that terminates within the ridge structure.
Short Ridge
Ridges of shortened lengths.
Fork or Bifurcation
The point at which one ridge divides into two ridges
Delta
The point on a friction ridge at or nearest to the point of divergence of two type lines.
Hook
A bifurcation with one short ridge branching off a longer ridge.
Eye
A single ridge that bifurcates and rejoins after a short course and continues as a single ridge.
Dot or Island
An isolated ridge unit whose length approximates its width in size.
Crossover
A point where two ridge units intersect.
Bridge
A connecting ridge between parallel running ridges, generally right angles
Enclosures
A single ridge that bifurcates around a dot or an island and rejoins after a short course and continues as a single ridge.
Specialty
Ridges that don't fall into any category.
Uses of R.U.V.I.S. (Reflected Ultraviolet Imaging System):
Locates prints on most nonabsorbent surfaces without using chemicals or powders.
Uses of Fingerprint Powders:
Locates prints on nonabsorbent surfaces using powder and camel-hair brush.
Uses of Magnetic Sensitive Powders:
Locates prints on hard/nonabsorbent surfaces using black magnetic powder.
Uses of Iodine Fuming:
To find fingerprints on paper, cardboard, unpainted surfaces.
Uses of Ninhydrin:
Visualizes latent prints on porous materials
Uses of Physical Developer:
Chemical mixture used for visualizing latent prints on articles that may have been wet at one time.
Uses of Cyanoacrylate/ Super Glue Fuming:
Household items: plastic, glass, skin.
Uses of Laser light/ Florescence:
Illuminates prints using florescent lighting and laser lighting.
Uses of Silver Nitrate:
Reveals the presence of a fingerprint (used as a last resort).
Latent Print Result of R.U.V.I.S. (Reflected Ultraviolet Imaging System):
Ultraviolet image converter detects latent prints and uses light to distinguish pattern of prints.
Latent Print Result of Fingerprint Powders:
Color depends on the powder color that is used but usually a darker color like black.
Latent Print Result of Magnetic Sensitive Powders:
Florescent powders and black powders are used to find latent prints.
Latent Print Result of Iodine Fuming:
Prints come out brown and when exposed to a starch mixture they turn blue and can last several weeks to months.
Latent Print Result of Ninhydrin:
Purple-blue print.
Latent Print Result of Physical Developer:
Colorless print but when exposed to UV light they appear black or reddish-brown.
Latent Print Result of Cyanoacrylate/ Super Glue Fuming:
White "frosty" print.
Latent Print Result of Laser light/ Florescence:
Visualize latent fingerprints with florescent lighting/ lasers.
Latent Print Result of Silver Nitrate:
Black or dark grey traces.