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Fingerprinting
ASISTM ProjectForensic Investigations
What are fingerprints?
On the fingers and palms of the hands and the toes and soles of the feet the skin is covered with friction ridges.
Photograph Paul Ricketts, 2006
Why do we have friction ridges?
Friction ridges are used to increase grip and the sense of touch.
Photograph Paul Ricketts, 2006
Friction ridges on the feet
Photograph Paul Ricketts, 2006
Friction Ridge Patterns
There are 3 main friction ridge patterns:• Loops - most common• Whorls• Arches - least common
Loop
Image courtesy J. Dook, 2006
Whorl
Image courtesy R. Henderson, 2006
Arch
Image courtesy J. Dook, 2006
Minutiae - fine detail
Image courtesy R. Henderson, 2006
Minutiae Patterns
Delta
Ridge ending
Bifurcation
Dot or island
Hook
Lake
Bridge
Image courtesy J. Dook, 2006
Example
Image courtesy J. Dook, 2006
Sweat Pores
It is possible to see small white “dots” on the friction ridges - the white dots are sweat pores.
Sweat pores
Image courtesy C. Henderson, 2006
Identical Fingerprints?
No two fingers have ever been found to possess completely identical friction ridge patterns.
Twins
RH: Left middle finger CH: Left middle finger
The boys both have a LOOP pattern but one of the twins appears to have cut his finger at some stage.
Image courtesy R. Henderson & C. Henderson, 2006
Twins Fingerprints
The minutiae or fine details of identical twin’s fingerprints are different.
Twins - minutiae
RH: Left middle finger CH: Left middle finger
Image courtesy R. Henderson & C. Henderson, 2006
How to take a fingerprint
An easy way is to use a pencil:
1) Rub an area on a piece of paper with a pencil. 2) Then rub your finger over the graphite on the paper. 3) Next, apply a small piece of sticky tape to the finger, lift and place
the tape on the sheet of paper.4) Make sure you clearly indicate from which finger the sample is
from.
An easy way to take a fingerprint
Photograph Paul Ricketts, 2006
An easy way to take a fingerprint -2
Photograph Paul Ricketts, 2006
An easy way to take a fingerprint -3
Photograph Paul Ricketts, 2006
Brushing for a fingerprint at a crime scene
Image courtesy J.Dook, 2006
Finding Fingerprints
Some fingerprints are obvious - these are called visible prints.
Photograph Paul Ricketts, 2006
Visible fingerprints on a door
Finding Fingerprints
Some fingerprints are NOT obvious - these are called latent prints.
How do you find latent prints?
Certain chemicals attach to substances that have been excreted by the sweat pores.
Using superglue
Using iodine
Using ninhydrin
References
Images• Fingerprints of J. Dook, R. Henderson and C. Henderson were
taken using a pencil as described on Slide 17. The prints were then scanned into Adobe Photoshop at a resolution of 1200dpi.
• J. Dook is the hand and foot model.• Slide 18 image taken of Police Constable Darren Fisher by J. Dook
at the Joondalup Police Academy, November 2005.• All other photography by Paul Ricketts, DUIT Multimedia, the
University of Western Australia.• Graphic design of slides by Trevor Hutchison, DUIT Multimedia,
the University of Western Australia.
