Chapter 4 - Fingerprints

Chapter Objectives
Why fingerprints are individual evidence.
 Define the three basic properties that allow
individual identification by fingerprints.
 Recognize the general ridge patterns (loops,
whorls, and arches).
 Explain the differences among latent, plastic,
and visible fingerprints.
 Develop latent prints (make them visible) using
physical and chemical methods.
Dactyloscopy The Study of Fingerprints
William Herschel—required Indians to put
their fingerprints on contracts, and used
fingerprints as a means of identifying prisoners
Henry Faulds—claimed that fingerprints did
not change over time and that they could be
classified for identification
Francis Galton—developed a primary
classification scheme based on loops, arches,
and whorls
Fundamental Principles of Fingerprints
A fingerprint is an individual characteristic.
A fingerprint remains unchanged during an
individual’s lifetime.
Fingerprints have general characteristic ridge
patterns that permit them to be systematically
Fingerprint classes
An arch has friction
ridges that enter on
one side of the
finger and cross to
the other side while
rising upward in the
middle. They do
NOT have type
lines, deltas, or
A loop must have
one or more ridges
entering and
exiting from the
same side. Loops
must have one
A plain or central pocket
whorl has at least one
ridge that makes a
complete circuit. A
double loop whorl is
made of two loops. An
accidental whorl is a
pattern not covered by
other categories.
Whorls have at least
two deltas and a core.
Whorls cont
Double Loop Whorl
Accidental Whorl
Fingerprint ridge characteristics
Fingerprint minutiae
Facts about fingerprints
60% of people have loops
 35% have whorls,
 5% have arches
How to make a print
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!
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.
Continue this process to make a fingerprint of all ten
fingers on the “My Prints” worksheet.
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