1788 - Johann Mayer
noted that the arrangement of skin ridges is never
duplicated in two persons. He was probably the first
scientist to recognize this fact.
1880 – Henry Fauld
working in Japan publishes fingerprint identify after case
where print was left on whitewashed wall
Rejected for Bertillon system for 20 years then adopted
1892 – Francis Galton
assigned fingerprints into 3 types
Loops, Whorls, and Arches
3 Fundamental Principles of
Fingerprints
① A fingerprint is an individual characteristic. No
2 people have been found to have identical ridge
characteristic
1 x 1020 chance of 2 people having identical ridge
characteristics
That’s 1 in 100,000,000,000,000,000,000!
② A fingerprint remains
unchanged during an
individual’s lifetime
- each print is composed of
valleys and ridges
- The ridges are believed to help
with grip
- Each ridge has multiple sweat
pores that lead to sweat glands
People have tried to change their
prints
 John Dillinger
(public enemy
#1)
③ Fingerprints have
general ridge patterns
that permit them to
be systematically
classified
Fingerprint Classes
There are 3 specific classes for all fingerprints based
upon their visual pattern: arches, loops, and whorls.
Each group is divided into smaller groups
Arch
Loop
Whorl
Arches, Loops, Whorls
Directions
1st – Roll the “pad” portion of your thumb over the
ink pad from the left side of your thumb to the
right. You do not have to push down really hard!
2nd – Roll the “pad” portion of your thumb from the left side of
your thumb to the right in the correct box on your paper to make a
thumbprint.
3rd – Continue this process to make a fingerprint of all ten fingers
on the “Data Table A” worksheet.
4th –Use your notes and a magnifying lens to help you figure out
what type of pattern is found in each of your fingerprints. Label
each one with the pattern’s name.
It’s time to make
some prints!
Avoid
Partial
Prints
GOOD PRINT
Get as much of the top part
of your finger as possible!
How do our fingerprint patterns
compare to the expected
averages?
Table C
Right Hand
Loop
Whorl
Arch
Left Hand
Let’s determine the rate of occurrence
for our fingerprint patterns ...
Pattern
Arch
Loop
Whorl
#
Total Prints
%
How do our results compare to the averages?
60% - Loops 35% - Whorls 5 % - Arches
__% - Loops __% - Whorls __% - Arches
Write a paragraph on your worksheet that summarizes our results.
Let’s determine the rate of occurrence
to compare males vs. females.
Pattern
#
Male
#
Female
Total
Prints
%
Arch
Loop
Whorl
Which pattern is most common pattern among the males in this class?
Which is most common pattern among the females?
How do the averages for each sex compare to the expected averages?
Characteristics of
Fingerprints
 Forensic examiners look for the presence of core
and deltas.
 The core is the center of a loop or whorl
 The delta is a triangular region where ridges
change directions
 A ridge count is another characteristic used to
distinguish one fingerprint from another.
 Draw an imaginary line from the center of the core
to the edge of the delta
Characteristics of Fingerprints
 Forensic examiners look for the presence of a core (the
center of a whorl or loop) and deltas (triangular regions
near a loop).
 A ridge count is another characteristic that distinguishes
one fingerprint from another. The count is made from the
center of the core to the edge of the delta.
Forensic Science: Fundamentals
& Investigations, Chapter 6
18
Interesting Info
Fingerprint Factoid:
60% of people have loops, 35% have whorls,
and 5% have arches
Did you know?
Dactyloscopy is the study of fingerprint identification.
Police investigators are experts in collecting “dactyl
grams”, otherwise known as fingerprints.
Arches
Arches are the simplest type of fingerprints
Formed by ridges that enter on one side of the print and exit on
the other.
No deltas are present.
Plain Arch
Ridges enter on one side and
exit on the other side.
Spike or “tent”
Tented Arches
Similar to the plain arch,
but has a spike in the center.
Loops
Loops must have one or more ridges that enter and leave on the same
side.
Have one delta
These patterns are named for their positions related to the radius and
ulna bones.
Delta
• To characterize a fingerprint as a radial or ulnar
loop, one must know from which hand it
came.
Ulnar loop
Radial loop
22
Ulnar Loop
Loop opens toward the
left or the radial bone.
(thumb)
Radial Loop
Loop opens toward
right or the ulna bone.
(toward Pinkie finger)
NOTE: On the left hand, a loop that opens to the left would be an ulnar
loop, while one that opens to the right would be a radial loop.
Whorls
Whorls have at least one ridge that makes (or tends to make) a
complete circuit. (4 types)
Have at least two deltas.
If a print has more than two deltas, it is most likely an accidental.
Plain
Whorl
Central
Pocket
Whorl
Draw a line between the two deltas in the plain and central pocket
whorls.
1) If some of the curved ridges touch the line, it is a plain whorl.
2)If none of the center core touches the line, it is a central pocket whorl.
Whorls – Part 2
Double Loop Whorl
Accidental Whorl
Delta
Delta
Double loop whorls are
made up of any two loops
combined into one print.
Accidental whorls contain two
or
more
patterns
(not
including the plain arch), or
does not clearly fall under any
of the other categories.
Accidental Whorl Double Loop Whorl
Central Whorl
26
Plain Whorl
Identify each fingerprint pattern.
Double loop Whorl
PLAIN WHORL
Right Hand
Left Hand
PLAIN ARCH
TENTED ARCH
Right Hand
ULNAR LOOP
Right Hand
Left Hand
Classification of Prints
 1st system: Henry system but could only handle 100,000
prints
 Today IAFIS has over 66 million (66,000,000) sets of
prints
 Today use FBI system, very similar to Henry system
 All prints will fit in 1 of 1,024 different groups
FBI System
 Pair up fingers in 5 fractions:
 R. Index







R. Ring
L. Thumb L. Middle L. Little +1
R. Thumb R. Middle R. Little
L. Index
L. Ring +1
Now look for presence of a whorl
If on the first pair = 16
If on 2nd pair = 8
3rd pair = 4
4th pair = 2
5 pair = 1
Add up 1 to numerator and denominator and all together
Example of FBI system
 If whorls were found on right index, right middle
fingers
 16 + 0 + 0 + 0 + 0 + 1
17/9
=
0+8+0+0+0+1
* 25% of population has a 1:1 ratio
Ridgeology: The study of the uniqueness of friction ridge structures
and their use for personal identification.1
As we have learned in our first lesson, a
fingerprint is made of a series of ridges and
valleys on the surface of the finger. The
uniqueness of a fingerprint can be determined by
the pattern of ridges and valleys
The koala is one of the few mammals (other than primates) that
has fingerprints. In fact, koala fingerprints are remarkably
similar to human fingerprints; even with an electron microscope,
it can be quite difficult to distinguish between the two.
Fingerprint Identification
When minutiae on two different prints match, these are called
points of similarity or points of identification.
At this point there is no international standard for the number of
points of identification required for a match between two
fingerprints.
However, the United Kingdom requires a minimum sixteen points
while Australia requires twelve.
Automated Fingerprint Identification System (AFIS)
AFIS is a computerized system capable of
reading, classifying, matching, and storing
fingerprints for criminal justice agencies. Quality
latent fingerprints are entered into the AFIS for a
search for possible matches against the state
maintained databases for fingerprint records to
help establish the identity of unknown deceased
persons or suspects in a criminal case.
http://www.fdle.state.fl.us/CrimeLab/images/fingerrint%20comparison%20for%20afis.jpg
AFIS CLOSE UP
Automated Fingerprint Identification System :
A network that scans crime scene fingerprints and compares them
with millions of prints collected by law enforcement agencies
around the world.
33
Livescan
 Don’t use ink much anymore,
but scan directly into the
computer
Minutiae
 Each individual has unique fingerprints. A fingerprint is
defined by the uniqueness of the local ridge characteristics
and their relationships.
 Minutiae points (aka Galton’s details) are the local ridge
characteristics.
 Identification points consist of bifurcations, ending ridges,
dots, ridges and islands.
 A single rolled fingerprint may have as many as 100 or more
identification points that can be used in order to identify the
individual.
Island
Dot
Bifurcation
Ridge ending
35
Ridge Characteristics
Use these characteristics as points of identification when comparing fingerprint
samples. The more points you can find in common, the better the match!
Minutiae Patterns
www.fbi.gov
37
Minutiae Patterns
www.fbi.gov
38
Ridge Characteristics
Crossover
Core
Bifurcation (fork)
Ridge ending
Scar
Island
Delta
Pore
How many ridge characteristics can you identify in this fingerprint?
http://www.dkfz.de/tbi/projects/bmcv/images/iu_it246_04s_fingerprint1.jpg
Try It!
1 – Blow up your balloon about halfway and twist the end to keep the
air from coming out. Do not tie it off!
2 – Use an ink pad to make a print with all of your fingers and label each
one with a permanent marker. Write your name on the balloon as well.
3 – Blow up the balloon to full size and tie the end.
4 – Analyze the fingerprints to find several ridge structures that we have
discussed. Use a highlighter to mark these structures on your “My
Prints” worksheet.
Think About It!
Which ridge structures were most common in your fingerprints?
Which ridge structures were most common in your group?
Were there any structures that were not found in any of the fingerprints?
Balloon Fingerprint Activity: http://www.msichicago.org/fileadmin/Education/learninglabs/lab_downloads/fingerprint_analysis.pdf
3 types of prints
① Visible prints
 Prints seen with naked eye in oil
(blood, paint, grease, ink)
② Plastic Prints
 Print impression left on putty, wax,
soap, or dust
③ Latent prints are impressions left by friction ridge skin on a
surface, such as a tool handle, glass, door, etc. that are invisible
to the naked eye.
Prints may be collected by revealing them
with a dusting of black fingerprint
powder.
Did you know? Camel hair is the most common animal
hair used to make fingerprint brushes. Now many
brushes (like the one above) are made out of fiberglass.
Powdering Techniques
 Always wear gloves
 Hold brush lightly between index finger and thumb
 Apply powder with tips of strands of brush
 Brush WITH the grain of the ridges
 Use fiberglass brushes for graphite powder
Some investigators use fluorescent powder and UV lights to help
them find latent prints on multi-colored or dark surfaces.
RUVIS Reflected Ultraviolet Imaging System
Magnetic powder can also be used to reveal latent prints. This
type of powder works better on shiny surfaces or plastic baggies
or containers.
The cyanoacrylate fuming method (often called the super glue
method) is a procedure that is used to develop latent fingerprints
on a variety of objects.
Ninhydrin is a chemical that bonds with the
amino acids in fingerprints and will produce a
blue or purple color. It is used to lift prints from
surfaces such as paper and cardboard.
Top Left: http://www.stapletonandassociates.com/images/MagPowder.jpg
Bottom Left: http://www.ok.gov/osbi/images/ninhydrin%20print.jpg
Bottom Right: http://www.forensicsrus.com/images/SupergluePrint.jpg
 Iodine Fuming
 Iodine sublimes and sticks to oils
 Silver Nitrate
 Sticks to salt in perspiration. Good for
porous surfaces or have even been wet at
one time
 If more than one method is used to develop prints, the order
in which the techniques are used is important. The following
order should be used to develop fingerprints:
IF MORE THAN ONE METHOD IS USED...
(1)
Iodine fuming
(2)
Ninhydrin
(3)
Silver nitrate
(4)
Superglue
fuming
 This is the procedure used for optimal visualization because
Iodine fuming is not permanent.
 If Ninhydrin fails, silver nitrate can be used but it will wash
away all the fatty oils and proteins from the surface.
 Superglue fuming, if used, must be used last.
48
Preservation of Prints
1) Always take a digital
picture of print
2) If small enough object,
wrap in cellophane to
preserve print
3) Or use piece of adhesive
(scotch tape) and then
stick to contracting
piece of cardboard
(mounting card)
Photographing Prints
 Photograph latent print life size 1:1
 If not 1:1 – fill the frame
 Use macro lens
 Include identification tag with scale
 Maintain photo log
Directions:
1 - Cover your table with white butcher paper or newspaper. You must dust
everything on the paper!
2 - Get a lifting kit from your teacher that contains black powder, brushes, and
clear tape.
3 - Press the pad of your right thumb on a CD or glass slide to make a print. Place
on the paper covering your table.
4 – Dip a brush lightly into the container of black powder and then tap off the
extra on the lid. You only need a very small amount of powder to dust the print.
5 – Hold the brush over the print and rotate it between your thumb and fingers.
Use the brush to remove any extra powder.
6 - Use a small piece of clear tape to lift the print and place it in the box on your
worksheet.
CAUTION: The black powder will be messy and isn’t easy to clean
up. Don’t dust anything without permission!
Clean Up
1 – Clean off the CDs or glass slides and put them back in the kit
with the brushes and tape.
2 – Have someone help you fold the paper in half and tap it to return
the extra black powder to the container.
3 – Put the black powder in the box and have it checked in by your
teacher.
4 – Get a towel and “dry” wash the table – especially the edges that
weren’t covered with paper.
5 – Get a wet towel to wash off the table and then wipe it with some
dry towels. Keep cleaning until all the black powder is off the table!
Bingo
1)
2)
3)
4)
5)
6)
7)
8)
9)
10)
11)
12)
Accidental Whorl
Central Pocket Whorl
Cynoacrylate
Delta
Double loop Whorl
Dusting for Prints
Francis Galton
Henry Number
IAFIS
Iodine Fuming
Latent
Minutae
13) Ninhydrin
14) Plain Arch
15) Plain Whorl
16) Plastic
17) Radial Loop
18) RUVIS
19) Tented Arch
20) Ulnar Loop
21) Visible
22) 10%
23) 30%
24) 60%