Fingerprinting Part 3Galton Details
Today’s Lesson Question:
How can fingerprints be individualized?
Students will be able to:
1)Identify individual
characteristics (Galton
details) in a fingerprint
pattern
Today’s Objectives
Why are fingerprint patterns (loop,
arch, whorl) considered class evidence?
FINGERPRINTS AS EVIDENCE

The 3 levels of fingerprint
classification:
1) pattern matching (a class
characteristic),
2) Galton details, and
3) ridge patterns (#2 and #3 can
both be used to individualize a
print).
Levels of Fingerprinting
Classification




The ridges of friction skin are not continuous,
but rather, contain numerous interruptions – the
Galton details.
These details are more commonly called
"characteristics" or "points of identity" and
consist of three basic types:
1)ridge endings
2)bifurcations (a ridge that divides)
3)Dots (or islands)
These "characteristics" or "points" are randomly
scattered during friction ridge skin formation and
their position, like all components of friction
ridge skin, are not duplicated from one individual
to the next or from one finger to the next.
Though a predetermined minimum number of points
are not required in order to make an
identification, the Galton details are usually
instrumental when an identification is made.
The Galton Details
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!
Ridge Characteristics
Crossover
Core
Bifurcation (fork)
Ridge ending
Scar
Island
Delta
Pore
http://cnx.org/content/m12574/latest/properties.jpg
Try It!
Students will identify as
many Galton details as
possible on the worksheet.
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