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ASISTM Project Forensic Investigations. Fingerprinting. 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? .
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ASISTM ProjectForensic Investigations Fingerprinting
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.
Why do we have friction ridges? Friction ridgesare used to increase grip and the sense of touch.
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 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 CH: Left middle finger RH: 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.
Image courtesy R. Henderson & C. Henderson, 2006 Twins - minutiae RH: Left middle finger CH: Left middle finger
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. • Next, apply a small piece of sticky tape to the finger, lift and place the tape on the sheet of paper. • 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.
Visible fingerprints on a door Photograph Paul Ricketts, 2006
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.
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.