Fingerprints
The Basics
T. Trimpe 2006 http://sciencespot.net
History of Fingerprints
HISTORY OF FINGERPRINTING


Chinese used fingerprints to
sign legal documents as far
back as three thousand years
ago
William Herschel, an English
civil servant (India), required
natives to sign contracts with
an imprint of their right hand –
Hindu custom?
HISTORY OF FINGERPRINTING


In 1880, Scottish physician, Henry
Fauld wrote that skin ridge patterns
could be important in identification work
A thief left his fingerprint on a
whitewashed wall – compared with 1st
suspect - No match; compared with
2nd suspect with positive association
HISTORY OF FINGERPRINTING
 Fauld
offered to set up a system of
fingerprints at Scotland Yard (at his
own expense)
 Rejected in favor of the Bertillon
System
 This decision reversed less than
two decades later
HISTORY OF FINGERPRINTING

The first systematic attempt at
personal identification was devised
and introduced by the French
police expert, Alphonse Bertillon,
in 1883.
Bertillon’s System
Relied on:
 Portraite Parlé – Detailed description of
the individual
 Full length and profile photographs
 Anthropometry – A system of precise
body measurements
ANTHROPOMETRY
A
method of identification
 Based upon the premise that the
dimensions of the human skeletal
system remained fixed from age 20 until
death
 Eleven (11) measurements taken
include height, width of head & length of
left foot
FRANCIS GALTON
In 1892, published the classic work
Finger Prints
 In this book he discussed the
anatomy of fingerprints and
suggested methods for recording
them
 Proposed three pattern types:
loops, whorls and arches

FRANCIS GALTON


No two prints are identical
An individual’s prints remain
unchanged from one year to
the next
SIR EDWARD HENRY
 Englishman
 In
1897, proposed another
classification system which is still in
use today
 Most English-speaking countries
use some version of Henry’s
classification system
Primary Classification
The Henry—FBI Classification
Each finger is given a point value
2
2
8
1
1
16
4
16
4
left
Chapter 4
8
Kendall/Hunt Publishing Company
right
12
Primary Classification
Assign the number of points for each finger
that has a whorl and substitute into the
equation; loops & arches are assigned zero.
right
right
left
left
left
index
ring
thumb middle little + 1
=
right
thumb
right
middle
right
little
left
index
left
ring
+1
That number is your primary classification
number
Chapter 4
Kendall/Hunt Publishing Company
13
Primary Classification
The Henry—FBI Classification
Each finger is given a point value
2 - Arch
1- Loop
2 - Loop
1 - Whorl
8 - Arch
8 - Whorl
16 - Arch
4 - Loop
16 - Whorl
4 - Arch
right
left
Chapter 4
Kendall/Hunt Publishing Company
14
Primary Classification
Assign the number of points for each finger
that has a whorl and substitute into the
equation: 8
1
right
right
left
left
left
index
ring
thumb middle little + 1
10
=
right
16 thumb
right
middle
right
little
left
index
left
ring
+1
17
That number is your primary classification
number 0.59
Chapter 4
Kendall/Hunt Publishing Company
15
In the
United States



1901 – First systematic use of
fingerprints adopted by the New York
Civil Service Commission
1904 – American police received training
in fingerprint techniques from Scotland
Yards representatives
1924 – Fingerprint records from the
Bureau of Investigation and Leavenworth
merged to form records for the new FBI
Admissibility of Fingerprints
Challenged in the case of United States v.
Byron C. Mitchell
 Argued under Daubert guidelines that
fingerprints were not unique
 Judge upheld admissibility and ruled:
1. Human friction ridges are unique
and permanent
2. Human friction ridge skin arrangements
are unique and permanent

PHYSIOLOGY OF
FINGERPRINTS
What are Fingerprints?



Friction ridge skin
pattern
Found on fingers,
palms, toes, soles of
feet.
Composed of ridges
(hills) and furrows
(valleys)
Black = Ridges
White = Valleys
19
What are Fingerprints?



Develop in early embryonic
development.
Pattern based on genetics,
detail somewhat random
Identical twins do not have
identical fingerprints
20
FUNDAMENTALS OF
FINGERPRINTS
FIRST PRINCIPLE:
Friction Ridges develop
their Unique form
in the fetus
FUNDAMENTALS OF
FINGERPRINTS
SECOND PRINCIPLE:
A Fingerprint will remain
LARGELY UNCHANGED
during an
Individual’s Lifetime
FUNDAMENTALS OF
FINGERPRINTS
THIRD PRINCIPLE:
Friction Ridge Patterns
and their details
are UNIQUE.
No Two Fingers have yet been
found to possess IDENTICAL
RIDGE CHARACTERISTICS (even identical
twins!!)
FUNDAMENTALS OF
FINGERPRINTS
FOURTH PRINCIPLE:
FINGERPRINTS CAN BE
SYSTEMATICALLY CLASSIFIED by
GENERAL RIDGE PATTERNS
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
as seen in the lists below.
Arch
Loop
Whorl
Plain arch
Tented arch
Radial Loop
Ulnar loop
Plain whorl
Central pocket whorl
Double loop whorl
Accidental whorl
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
“dactylograms”, otherwise known as
fingerprints.
Arches
Arches are the simplest type of fingerprints that
are formed by ridges that enter on one side of the
print and exit on the other. No deltas are present.
Spike or “tent”
Plain Arch
Ridges enter on one
side and
exit on the other side.
Tented Arches
Similar to the plain arch,
but has a spike in the
center.
Loops
Left Hand
Loops must have one delta and one or
more ridges that enter and leave on
the same side. These patterns are
Ulnar
named for their positions related to
the radius and ulna bones, i.e. the
bone that the loop opening is facing
towards. Help: “UP RT” Ulnar Pinkie side
Right Hand
Ulnar
Radius
Radial Thumb side
Delta
If Left Hand – Radial Loop If Left Hand – Ulnar Loop
If Right Hand - Ulnar Loop If Right Hand - Radial Loop
X-Ray Imagine: http://www.tooloop.com/wp-content/uploads/2013/12/Radius-Ulna-X-Ray.jpg
Whorls – Part 1
Whorls have at least one ridge that makes (or tends
to make) a complete circuit. They also 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. If some of the curved ridges touch the line, it is a
plain whorl. 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
Delta
Plain Arch
Delta
Delta
Double loop whorls are Accidental whorls contain two
made up of any two loops or more patterns (not including
combined into one print.
the plain arch), or does not
clearly fall under any of the
other categories.
Minutiae, also known as ridge characteristics.
They help create unit ridge patterns.
Bifurcation
Dot
Island
Ridge
Ending
31
 How
many ridge comparisons are
necessary to identify two
fingerprints as the same?
Range
of 8-16
comparative points
Identify each fingerprint pattern.
Right Hand…
1. Deltas? Zero=Arch
One=Loop
Two=Whorl
2. Arch? No center spike=Plain
Center spike=Tented
3. Loop? Thumb=Radial
Pinkie=Ulnar
4. Whorl? Touches Delta Line=Plain
No touch Delta Line=Central Pocket
Two loops wrapped together=Double Loop
Two + patterns fitting other category=Accidental
Left Hand…
Right Hand…
Left Hand….
Right Hand….
It’s time to make
some prints!
Avoid
Partial
Prints
GOOD PRINT
Get as much of the top part
of your finger as possible!
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 “My Prints” 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.