Fingerprints are common evidences found at the crime scene. This presentation include methods for development of latent fingerprints. To know more about the topic, follow the link given- https://youtu.be/yQjxkntFH0k

2. DEVELOPMENT OF LATENT
FINGERPRINTS USING POWDERS
METHOD (PART-I)
By-
Vaishnavi Puli
Volunteer of Applied Forensic
Research Sciences

3. CONTENT
• Introduction
• Types of fingerprints
• Collection of patent and plastic prints
• Development of latent fingerprints by physical methods
• Historical perspective

4. INTRODUCTION
• Fingerprints are distinctive ridges appearing as corrugated lines on the tips of
fingers and thumbs. Corrugation results due to rising of the portion of upper
layer of the fingertip skin slightly above the normal level. Since the upper layer
of skin is called as epidermis the finger ridges are also referred to as
“Epidermal ridges” or “Friction ridges”
• The pattern on each finger of a person is unique that it is not repeated on another
finger of the same person or on the fingers of other person. This makes
fingerprints the most infallible means of identification.
• This identification mark of an individual is used as a investigative tool in
criminal cases. Hence fingerprints found at the crime scene lead to more
suspects and generate more evidences in the court than all other forensic
techniques combined.

5. TYPES OF FINGERPRINTS
• There are 3 types of fingerprints they are:
1. Patent prints
2. Plastic impressions
3. Latent fingerprints

6. 1.Patent Prints:
• Visible print by unaided eye.
• Good example of patent print would be a greasy impression
left on a window.
• Also blood, paint, ink, mud , dust…
2. Plastic Impressions:.
• These are formed when the raised Friction ridge’s are
physically pushed into substrate, creating a mold of the
friction skin ridge clay, soft wax, melted heavy grease, paint
and so on….
• These impressions are 3D in nature.
• And easily visible to human eye as patent Prints and do not
require any additional processing for visible purpose.
Patent print of blood
Plastic Impressions

7. 3.Latent fingerprints
• The word latent means Hidden or unseen.
• Latent Prints are “Undetectable” until brought out with a physical or chemical process to
enhance latent print residue.
• A latent print residue is mixture of secretion from glands.
• Two major glands in dermis are sebaceous glands and sudoriferous glands.
• The print is 99% water and rest is trace amount of amino acids, lipids, urea, lactic acid,
creatinine, glucose and drugs.
• The investigators use a general method of oblique lighting to locate latent prints at the
scene of crime.
• After locating these prints we use certain physical and chemical methods to develop
these fingerprints.
Latent fingerprints

8. COLLECTION OF PATENT AND PLASTIC PRINTS
Patent prints:
Patent prints are usually Photographed for subsequent identification.
Plastic Impressions:
• Plastic impressions are generally collected and preserved by “Casting”.
• A liquid material such as silicone rubber, plastic, POP, or a metal alloy is poured over the
fingerprint and hardened to make a cast of the impression.
• The cast is much more durable then plastic print and further stored as an evidence.

9. DEVELOPMENT OF LATENT FINGERPRINTS
BY PHYSICAL METHODS
• Physical methods for developing latent fingerprints comprises the use of various types of
“Powders” hence we can also call this method as “Powders method”.
• The powders technique for detecting latent prints involves the application of finely
divided formulation to the finger mark impression generally using a “Glass fibers or
Camel hair brush”.
• The powder gets mechanically adheres to the sweat residue detecting the ridge pattern.
The furrows which are devoid of fingerprint residue do not adhere the powder on to
them. The final outcome is that the powder formulation sticks to the ridges but is easily
blown of the furrows. Since the powder is normally colored the ridge pattern become
visible and the latent print is said to be developed.
Camel hair brush Fiber glass brush

10. HISTORICAL PERSPECTIVE
• The used fingerprint powders dates back to last decade of the 19th century. “Sir
Edward Richard Henry” from 1850-1931 who devised the fingerprint
classification formula recommended the use of Mercury based and Graphite
based powders. The formal formulation is called as “Hydragyrum Concrete”
was composed of one part of Mercury (Hg), 2 parts of chalk by weight.
• The powder was useful for developing latent prints on Non- absorbing surface
such as glass and dark painted lackward utilities.
Disadvantages of Hydragyrum Mercury Formulation
• The formulation was withdrawn inn1967 because the Mercury content could be a
health hazard. Moreover it was ineffective for develop prints on gold ornaments
as mercury reacts with the gold and mard it’s surface.
• The graphite based powders was very useful for developing imprints on Silver
painted object.. However, even this powder was withdrawn since it was messy to
use particularly if the examination was to be carried out in open and strong wind
was blowing.
Sir Edward Richard
Henry

11. • Today there are number of powders which are available in market
required for the purpose of detection of the latent fingerprints
• Depending on the surface color and surface texture these powders
can be applied.
• The various types of powders which are available are comprises of
• Black powders
• Magnetic powders
• Non-magnetic powders
• Flourescent powders
• All of these powders work on the same mechanism.

12. MCQ TIME
• The formulation of “Hydragyrum concrete” composed
of……….
A. One part of Manganese(Mn) and one part of water by weight
B. Two parts of Mercury (Hg) and one part of water by weight
C. One part of Mercury (Hg) and two parts of chalk by weight
D. One part of Aluminum (Al) and one part of Lead (Pb)

13. Thank You