Fingerprints: Your Personal
Signature
Fingerprint History
• Pre-History-Early potters identify their works with an
impressed fingerprint
• 1000BC-Chinese sign legal documents using fingerprints
• 1685-Marcello Malpighi first recognizes and describes
fingerprint patterns.
• 1823-JohannesPurkinjie establishes 9 basic fingerprint
patterns and rules for classifying them.
• 1858-Sir William Herschel first notes the individuality of
handprints, and finds they remain unchanged after 50
years.
Fingerprint History Cont
• 1892-Sir Francis Galton publishes the textbook Finger
Prints in which he offers convincing evidence that no
two prints identical.
• 1899-Sir Edward Henry devises a classification
system based on five types of prints. This system is
the basis for ones used in the US and Britain today.
• 1910-Thomas Jennings becomes the first person
convicted in the US on fingerprint evidence.
Anthropometry: A Precursor to
Fingerprinting
• Anthropometry is the science of measuring
humans.
• First developed by Alphonse Bertillon, and
became known as Bertillonage in the late 19th
century.
• System collected numerous body measurements
and categorized various facial features of a
person
– According to Bertillionage measurements the odds of
two people being the same where 286 million to one.
Difficulties with Bertillionage
Measurements
• A Bertillionage catalogue included:
– Photographs of each person
– A set of complex anthropometric measurements
and feature classifications were collected on a
card.
• The complexity of the system made it difficult
and it gave way to a new identification
method—fingerprinting—in early 20th
century
Anatomy of a Fingerprint
• Finger pads-Fleshy service of the finger used
for touching and gripping.
• Grooves, and friction ridges arranged in
patterns.
Ridgeology
• Ridgeology: The study of the uniqueness of
friction ridge structures and their use for
personal identification.
• The uniqueness of a fingerprint can be
determined by the pattern of ridges and valleys
as well as the location, shape, and position of
minutiae points.
– Minutiae are points where ridge structure changes
Basic and composite ridge characteristics
(minutiae)
Example
Minutiae
Short Ridge
Bifurcation
Bridge
Dot
Double Bifurcation
Enclosure (Lake)
Example
Minutiae
Trifurcation
Hook
Opposed Bifurcation
Opposed Bifurcation/
Ridge Ending
Ridge Crossing
Ridge Ending
Classifying Prints
• Patterns:
– Arches
• Ridgelines that rise in the center to create a wavelike
pattern. Subgrouped into plain or tented. Only 5% of
all pattern types are arches.
Plain
Tented
Classifying Prints Cont
– Loops-comprised of one or more ridges that double
back on themselves. About 60% of patterns in human
fingerprints are loops.
• Radial loops flow downward toward the radius (thumb side)
Classifying Prints Cont
• Ulnar loops flow downward toward the ulna (little finger)
side.
Classifying Prints Cont
– Whorls-Look like little whirlpools of ridgelines. They
are characterized by 2 or more deltas. Whorls make
up 35% of patterns in human fingerprints.
• Plain Whorls-are either concentric circles or spiral
Delta
Delta
Classifying Prints Cont
• Central pocket loop whorls-resemble a loop with a
whorl at its end.
Classifying Prints Cont
• Double loop whorls-Include two loops that collide to
produce an S-shaped pattern
Classifying Prints Cont
• Accidental loop whorls-Slightly different from other
whorls and are irregular.
Quick Tips
• If a fingerprint has no deltas, it is an arch.
• If a fingerprint has one delta, it is a loop.
• If a fingerprint has two or more deltas, it is a
whorl.
The Henry Classification System
• Developed by Sir Edward Henry in the late
1800s for criminal investigations in British India.
• Was the basis of modern day AFIS classification
methods up until the1990s.
• Using the Henry system, individual prints are
assigned scores based on where a whorl shows
up within a 10 finger set of prints.
The Henry Classification System Cont.
L
L Ring
L
Pinky
Middle
L
Index
L
R
R
Thumb Thumb Index
R
Middle
R
Ring
R
Pinky
Finger #
10
9
8
7
6
1
2
3
4
5
Value (if
Whorl is
present)
1
1
2
2
4
16
16
8
8
4
The Henry Classification System Cont.
• The fingerprint record’s primary grouping is
determined by calculating the ratio of one plus
the sum of the values of the whorl-patterned,
even-numbered fingers; divided by one plus
the sum of the values of the whorl-patterned,
odd-numbered fingers
• 1+((Sum whorled, Even finger value)
(Sum whorled, Odd finger value)) =Primary
Grouping
Ratio
The Henry Classification System
Problems
• This system separates fingerprint files into
1,024 groups.
• Investigators then had to analyze the minutiae
by hand in order to match the prints.
• Analyzing and matching a set of prints could
take months
• Criminals did not always leave behind a full set
of 10 prints.
AFIS technology (Automated
Fingerprint Identification System)
• Collaboration between the FBI and the National
Institute of Standards and Technology(NIST) in
the 1960’s
• The Henry Classification System has been a highly
influential force in the formation of current AFIS
technology.
• Primarily envisioned used as a tool to expedite
the manual searching of fingerprint records,
eventually reducing matching time requirements
from months to hours.
AFIS Technology Cont.
• Up until the mid 1990s, it was not unusual for
a state or city to continue to maintain its
physical file of Henry-sorted fingerprint cards
just in case a disaster occurred in the AFIS.
• AFIS began to classify fingerprints according to
the distance between the core and delta,
minutiae locations, and pattern type.
Interesting Facts
• Did you know?
– Police investigators are experts in collecting
“dactylograms”, otherwise known as fingerprints.
– 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.