1

Fingerprints

Visible prints

Visible prints

2

Fingerprints

Latent prints

Requires chemical visualisation

Visible prints

3

Origin of Fingerprints

Secretions from skin glands

Metal salts e.g. sodium chloride

Amino acids & proteins

Fats

Water

4

Fingerprint Visualisation

Dusting powder

Physical adhesion

to a fingerprint

5

Molybdenum disulfide

Dusting powders

Carbon black

Aluminium

Contrast with the background

6

White surface

Dusting powders

Molybdenum disulfide

Carbon black

Aluminium

Contrast with the background

7

Dusting powders

Dark surface

White surface

Molybdenum disulfide

Carbon black

Aluminium

Contrast with the background

8

Fingerprint Visualisation

Lifted fingerprint

Powder is lifted

off onto a tape

Photographed

and preserved

9

Chemical reagents

Ninhydrin

Iodine spray

2

1

Apply and heat

Silver nitrate

3

Reacts with amino acids

10

Physics-based methods

Alone

Using a dye

Laser fluorescence

11

“Superglue”

Fuming Cyanoacrylate

12

“Superglue”

Fuming Cyanoacrylate

Masato Soba

Fuseo

Matsumura

Superglue is

deposited on

the fingerprint

Make it visible

Commercial fumehood

13

Fume chambers

Can then add dye

and use a laser

Fuming Cyanoacrylate