PANCHYAT degree COLLEGE, BARGARH
(Department of chemistry)
Fingerprint Detection
Method
And The Use of
Chemistry
By:-
Jhasketan Meher / S04521CHE021
Content:
Types of fingerprint
m
Development of
fingerprint
Physical
bha
s u
-Powder
@
-Laser
Chemical
-Reagent
-Fuming
-Bloody
Types of fingerprint on Crime Scene
1.Visible Prints
• During the course of time the suspect's hands may get
contaminated with a number of external contaminants like
powder , soil, grease, paint or blood .
2. Plastic Prints
• The three dimensional print occurs when the suspect hands are
pressed against soft or plastic substance like butter, clay etc. are
called Plastic Prints.
3. Latent Prints / Invisible Prints
• Invisible print created by transfer of body perspiration or oil
are latent print.
Development of Latent
Fingerprints
2. Chemical
Methods
1. Physical Methods
•Reagent
• Powder • Fuming
• Laser • Bloody
Physical Methods : Non porous
1.Powder Method
It is the oldest and most
widely used method and can
be considered as quite
convenient
Squirrel hair brush or camel
hair brush are used.
Generally useful for non
porous surfaces.
The following powders are
used:
1.Black Powder (Charcoal ,
Graphite , Lampblack)
- Excellent for chinaware and smooth
surfaces.
- If to be applied to porous surface
should be used with Magnesium
Oxide.
2. Red Powder (powered resin of
palm fruit)
- Excellent for paper with fresh prints
4. White (Titanium Oxide, Zinc oxide and Resin
Acacia)
- Excellent for glass, silverware and plated ware.
- Aluminium Dust(silver dust)
- Excellent for cellophane, feathers, polished,
painted and varnished surfaces.
5. Fluorescent Powder ( Anthracene and
Rhodamine-B)
- Useful for coloured surfaces
2. Laser
• Fingerprint contents like ink, blood, oil and other substances
when placed under laser along with suitable filter above various
fluorescence .
• It is useful even in very old prints even as old as 10 years.
Chemical Method:
1.Chemical reagent
• Useful in old prints both porous
and nonporous surface.
Ninhydrin Method
When Ninhydrin comes in contact
with amino acids of perspiration it
gives a pinkish purplish print.
Silver Nitrate.
Reacts with Sodium Chloride
present to give Silver Chloride which
is a highly photosensitive
substance.
It turns black when exposed to light.
Osmium Tetroxide
React with oils and fats to give black
prints .
2 .Fuming Method:
Useful for porous material like cardboard, paper and
wood, etc.
Iodine Method :
Iodine starts sublimating, so in a beaker some crystal of
iodine is taken and the latent fingerprint is taken above
that and heated for better results . So the heated iodine
crystal reacts with the oil and greasy substance present
on the fingerprint and the fingerprint is visible
to the naked eye.
Superglue Fuming Method:
Superglue is 99% cyanoacrylate ester
When it is put on a beaker and then the fingerprint is
taken above that so after 24 hours the fingerprint is
obtained as colour one.
3. Bloody fingerprints
Often available at violent crime scenes.
DFO
- 1,8 Diazafluoren 9 one when exposed to blood gives fluorescent or
coloured prints.
AMINO ACID
Develop black fingerprint when exposed to blood .
THANK YOU
@subhammehe
r07
