2. 1 .Patent Fingerprint (Visi
ble)
2 .Latent Fingerprint (Invisible
)
3 .Plastic Fingerprint
WHAT IS A FINGERPRINT ?
A Fingerprint is the impression left by a finger's F
riction ridges upon contact with a Surfaces.
TYPES OF FINGERPRINT
3. Patent Fingerprints (Visible Fingerprints)
Patent Fingerprints, on other hand can be made by blood,Grease,i
nk or dirt.This type of fingerprint is easily visible to the human ey
e.
4. Latent Fingerprints (Invisible Fingerprint)
Latent Fingerprint are made of the sweat and oli on the skin's surface.
This type of Fingerprint is invisible to the naked eye and requires additional
methods & techniques to be seen.
5. Plastic Fingerprints (D)
Plastic Fingerprints are three-dimensional impressions and can be mad
e by pressing your finger in fresh paint, wax, soap, gel, ect. Just like pat
ent Fingerprint, plastic Fingerprint are easily seen by human eye and do
not require additional processing for visibility purposes.
6. FINGERPRINT DETECTION METHOD
Fingerprint development with Poweders
Superglue fuming & Iodine fuming
Vaccum Metal Deposition (VMD)
Small Particle Reagent (SPR)
Ninhydrin Test
Silver Nitrate Method
Physical Developer
7. TYPES OF SURFACES
For Non-Porous surface,eg. Glass, gloss-painted surfaces, metal,
treated wood and plastic. materials that air or liquid can't pass t
hrough & surface is smooth and clean.
Test: FP Poweders,Fuming,VMD, SPR
For PorousSurface, eg. Paper, wall-paper, carboard, carpet, untreated wo
od and matt emulasion painted surfaces.Porous surfaces are made from
materials that naturally have small holes, or pores, inside themThe reage
nts used for these surfaces react either with amino acids, fats, and lipid or
chlorides absorbed into the surface.
Test: DFO, Ninhydrin,Physical developer, silver nitrate method.
8. Applied in white colour surface.
Black Carbon Cha
rcoal & Mercury
Fluorescent fingerprint powders ar
e designed to develop latent finger
prints on multi coloured surfaces.
Anthracene Poweder
We can spread this Poweder over t
he surface with the help of magnet(
kehna brush)
Metal & Metal Oxides
This Poweder is used on dark Surfa
ce or Metal Surface or mirror surfac
e.
Alluminium Du
st
In case of contaminated Surface, wh
ite Poweder are more suitable.
Lead Carbonate or
French Chalk
Types of Fingerprint development Poweders
Black
Poweder
White
Poweder
Fluorescent
Poweder
9. Superglue fuming & Iodine fuming
• Also known as cyanoacrylate fuming
• It is composed of methyl or ethyl cyanoacrylate which
polymerize with latent prints.
• It reacts with fatty acids and amino acids
• It is one of the oldest and cheapest methods and can
develop recent prints on porous and non-porous surfaces
like cloth, skin, paper etc.
• Iodine fumes are absorbed by fingerprint’s fats and oils to
form a brown image which is photographed immediately
because iodine is volatile. If starch water is sprayed it can be
preserved for months. Color is blue with starch.
10. Vaccum Metal Deposition
• VMD is most sensitive, being capable of detecting
monolayer of fat by sequential deposition of a thin
coating of thermally evaporated gold followed by
zinc.
• It can develop fingerprints on surfaces that have
previously been wet or even submerged in water for
extended periods of time.
• Fingermarks developed by VMD are of a much
higher definition (often to 3rd level detail) and have
superior contrast as compared to other techniques.
• If fingerprints are not revealed by VMD, superglue,
powders or other techniques may be used
subsequently.
11. 01
02
03
SPR consists of a suspension o
f molybdenum disulfide suspe
nded in aqueous detergent sol
ution which is applied by spray
ing or immersion.
The molybdenum disulfide parti
cles adhere to fats deposited in
the fingerprints,
Final color: A gray-black image.
Small Particle Reag
ent
12. Ninhydrin Test
• 1st time used by Oden and Hofsten.
• Ninhydrin can be considered as the2,2-Dihydroxyindane-1,3-dione
• Ninhydrin is a widely used chemical which reacts with amino acids and produces a deep blue
or purple color known as Ruhemann's purple.
• Very slow technique. Temperature increased to increase rate, heat at 26⁰C-38⁰C. Samples as old
as 50 years also developed.
• Procedure: First, a 2% solution of ninhydrin must be prepared by dissolving 0.2 grams
of ninhydrin in 10ml of either ethanol or acetone. Now a 1% solution of the amino acid
(analyte) in distilled water must be prepared. A few drops of the 2% ninhydrin solution must
be added to this solution.
Ruhemann's purple
Ninhydrin
13. Silver Nitrate Method
• Reaction of silver nitrate with chlorine
present in the fingerprints.
• Effective for porous paper, cardboard,
plastic, wood. Prints on wet articles
can’t be developed.
• Silver nitrate reacts with chlorine to
form silver chloride giving us a gray
color on visualizing under UV.
14. Physical Developer
• It is the only available technique for detecting fingerprints on a wet
porous surface.
• This reagent is an aqueous solution of silver nitrate containing a Fe II/III
redox couple and two detergents- Citric acid and dodecyl amine acetate.
• Absorption of metallic silver particles of fatty acid and lipids.
• The developed fingerprints are gray-black in color and recorded using
conventional photography.
