Fingerprints

9/2/2015 1Finger Prints
Finger Prints

9/2/2015 Finger Prints 2
Fingerprints
 A fingerprint is an imprint made by the pattern of ridges on the pad of a human
finger.
These ridges are known as dermal ridges.
Fingerprints ridges are formed during the third to fourth month of fetal development.
The ridges begin to develop on the skin of the thumbs and fingers.
The purpose of these ridges is to give the fingers a firmer grasp and to avoid slippage.
These ridges allow the fingers to pick up objects.
The friction ridges on the fingers arrange themselves in more or less regular patterns
with ridge characteristics.
All fingerprint have a unique combination and arrangement of patterns and ridge
characteristics.
These patterns of friction ridges contain rows of sweat pores that allow sweat and oil
to exit from glands.
Sweat mixed with other body oils and dirt produces fingerprints on smooth surfaces.
Fingerprints are left, by the transfer of oils or amino acids to a surface, from the
transfer of substances on the fingers like paints or blood or by leaving an impression
print in a soft substances.

9/2/2015 3Finger Prints
 No two prints have ever been found to be exactly alike, even those of identical twins
are different.
 Fingerprints are not inherited.
After formation, the growing fingerprint ridges expand uniformly in all directions
while growth is occurring so the pattern never changes.
Fingerprints cannot be altered without creating a new unique fingerprint. Even when
the skin tissue is injured, the skin that grows back will have the same print.
Print remain the same throughout life.
The prints that someone is born with won’t change until decomposition after death.
The anatomical formation of friction ridges, the stage of friction ridge development on
the human fetus and, most importantly, explain differential growth (random physical
stresses and pressures) of friction ridges which is the major premise of friction ridge
identification.
 The friction ridges are found on the digits, palms and soles. They are called ‘ friction’
ridges because of their biological function to assist in our ability to grasp and hold onto
objects.
Ridges vary in length and width, branch off, end suddenly and, for the most part, flow
in concert with each other to form distinct patterns.
The ridges path can sometimes be quite fragmented so much so as to show what
appears to be individual ridge “ units” present on the volar surface.

 Each ridge “ unit” corresponds to one primary epidermal ridge (glandular fold) formed
directly beneath each pore opening.
 Friction ridges are in their definitive form on the fetus before birth once this blueprint
has been established, in the stratum basale (generating layer) of the epidermis on the
fetus prior to birth ,it does not change except for injury, disease or decomposition after
death. Injury to the generating layer may affect the skin ability to regenerate and scar
tissue forms.
 Location and size of pore ducts and pore openings along the surface of friction ridge
skin are also in their definitive form before birth and do not change.
 The basic fundamentals in the science of fingerprint identification are:-
 Permanence
 Individuality
 When doctors state that twins have the same fingerprints, they are referring to the
class characteristics pattern.
 These loop, arch and whorl ridge flow patterns have nothing to do with the individual
characteristics used to positively identify persons.

Pattern Area
The pattern area is that part of a loop or whorl in which appears the cores, deltas,
and ridges.
 It is present in all patterns but in many arches and tented arches it is impossible to
define.
 Delta- The first fork or bifurcation nearest the center of divergence. The delta need
not be a fork but may be any type of ridge formation like bifurcation, dot, short
ridge, meeting of two ridges.
 The delta may not be located at bifurcation which does not open towards the core.
 If there is a choice between a bifurcation or some other type of delta, the
bifurcation is selected.
 The delta may not be placed in the middle of a ridge running between the types
lines, but only at the nearest end of the ridge.
 Core- The approximate center of the pattern area.
The core can be any form such as a staple, uneven numbers of rods, even number
of ridges or pair of staples.
The core is located on or within the innermost looping ridge.

Ridge count of the pattern
The method of counting ridges differs in loops and whorls .
•Loops:-
• The core and delta are not counted.
•A white space must come between the first ridge and the delta. This condition defines
the first ridge.
• If there is a bifurcation on the line of count, two ridge are counted.
• Dots and short ridges are counted if they are cut by the line and are heavy and thick.
• Whorls:-
• To distinguish the various types of whorls the symbols, I, M, and O are used for Inner,
Meeting and Outer whorls.
• The deltas are located.
• the number of ridges between the tracing between the tracing line and the right delta is
counted.
• If the traced ridge passes inside or above the right delta with three or more intervening
ridges between the traced line and the delta, the whorl is called inner and it is indicated
by the letter “ I”. If the ridge passes outside (below) the right delta, the whorl is termed
outer “O” and if it is meets the right delta or not more than two ridges intervene when
passing in side or outside of the delta, the whorl is called a meeting whorl “M”.

Arch Loop Whorl and Composite
Types of pattern and their description
The basic fingerprint patterns can be conveniently divided into the
following eight types under three pattern groups
Plain Arch
Tented Arch
Radial Loop
Ulna Loop
Plain Whorl
Central/Lateral
Pocket loop
Twinned Loop
Accidental Whorl
PATTERNS

Arch Pattern
In an arch pattern, ridge flow in one side and flow out the opposite side of the impression
without making any backward turn, the ridges rising slightly in the middle.
 There are no deltas in an arch pattern.
 Arch pattern account for 5% of all fingerprints.
 There are two types of arch patterns:-
 Plain Arch- This is made up of a series of ridges that enter from one side of the pattern and
flow without interruption across the finger, terminating at the outer side after a slight rise in the
centre. There are no recurving ridges in the true arch.
 Tented Arch- This is similar to the plain arch except that there is sharp rise in the centre of the
pattern.
A very sharp peak is noted in most tented arches and a definite angle is formed by the upward
thrust of the ridges.
Loop Pattern
 A loop is formed by one or more ridges entering at one side of the pattern, continuing up to the
centre of the pattern, and recurving around a core to form a loop, then flowing in the opposite
direction and terminating on the same side from which they entered.
 The recurving ridge pass freely between the core and the delta.
 A series of such ridges permits a ridge count between the delta and the core, following an
imaginary straight line between these two points.
Loop patterns account for 70% of all fingerprints.

Essentials of a loop
 A sufficient recurve
 One delta and one core
 A ridge count across a looping ridge.
Radial Loops- Radial loops are those that have a flow of ridges starting and terminating in
the direction of the thumb of the same hand on which they are found.
 Ulna Loops- The term ulna denotes a trend of flow of the ridges in the direction of the little
finger of the hand. On this side of the forearm is a small or ulna bone, which joins the hand in
line with the little finger.
 Loops are divided into radial and ulna according to the way they flow on the hands and not
according to the arrangement on the fingerprint card.
 It is impossible to know whether a loop is ulna or radical unless it is known from which hand
the impression was obtained.
Whorls Pattern
A whorl pattern consists of a series of almost concentric circles.
The whorl type of pattern has at least two deltas with a recurve in front of each.
 This occur in about 30% of all fingerprint
 Alteast one encircling ridge around the core
Two deltas and one core.

 Plain Whorl
 A whorl is a pattern in which one or more ridges appear to revolve around a centre
point called the core, often making a complete circuit.
 The whorl type of pattern has at least two delta.
 Deltas in whorls can be found very close to the core or at any point extending out
to the extreme edge of the impression, but never above an imaginary horizontal line
running through the centre of the pattern.
 In the whorl pattern an imaginary straight line drawn between deltas will cut one
or more of the recurving ridges that completely encircle the core.
 All whorls are not circular in shape, but may be elliptical or oval.
Composite Pattern
• The type which include the combination of two or more pattern are called as Composites.
• These are of four kinds :-
• Central Pocket Loop- This is a pattern in which some of the ridges have the appearance of
a whorl near the core and the others have that of a loop.
• The ridges that surround the pattern area form a pocket hence it is called central pocket loop.
• Central pocket loop contains two deltas.
• Twinned Loop (Double Loops)- These contain two loops and the loops are formed in such
a manner as if they embrace each other.
• They have two cores and two deltas.
• In these the deltas occur on the either side of the ascending loop.

• These consist of two separate and distinct loop formations with two separate and distinct
shoulders for each core.
• Lateral Pocket Loop- It is composed of two distinct loops surrounding each other and is often
confused by the in experience with the twinned loop.
• In this pattern, both the loops flow in a lateral direction and both terminate either above or
below the same delta.
• Accidental- This is a complicated type having the appearance of two or more patterns.
•This type generally possesses three delta and sometimes more are also found.
• Accidentals are, however, very rare and that is why are named as such.

Ridge Characteristics /Types of Minutiae.
•Ridge End/ Termination
•Short Ridge
•Bifurcation
•Lake or Enclosure
•Dot
•Spur/Hook
•Crossover
•Intersection
•Incipient Ridge
•Fragmentary Ridge

Classification of Numerical Indexing
1. Primary Classification-
• Patterns are first divided into numerical and non numerical patterns
• Whorls and composite patterns are numerical patterns.
• Whereas, Arches and loops are non numerical patterns.
• All the rolled impressions are numbered in the Henry system.
• Fingers that have a whorl pattern are used to define a primary grouping for the set
of fingerprints.
• A number is assigned to those fingers that have a whorl pattern.
• Fingers that do not have a whorl/composites are given a finger value of zero.
• Only fingers with a whorl/composites pattern are assigned a number other than
zero.
• The value of 1 added to each sum of the whorls with the maximum obtainable
being 32.
• 1/1 would indicate no whorl pattern and 32/32 would mean that all fingers had
whorl patterns.
• The Henry Classification System allows up to 1024 Primary groupings.

Secondary Classification
• The secondary is obtained from the pattern types present in the index fingers.
• Number two fingers is the Numerator
• Number seven fingers is the Denominator
•Sub Secondary Classification
•Final Classification
Finger Print Developing Technique
The constituents percentage of sweat are as follow:
Water
Urea
Fat, fatty acids and Amino acids
Sodium Chloride and other Salts
Sweat glands become more active during that time due to nervousness than normal
period. The impressions on the articles are not visible to the naked eye. Only in some
articles fingerprints are visible to the naked eye.

Types of Prints
o Visible Prints/ Patent Prints-
o Visible Prints are those left behind of scene of offence on account of fingers or
palm coming into contact with some colored material such as:-
oPaint
o Ink
o Dirt
o Blood
o Tar
o These kind of chance prints are clearly visible to the naked eye and can easily be
recorded by taking photographs with or without use of filters.
oPlastic Print/ Moulded Print- These types of prints are generally found on
Flexible surface like:-
o Soap
oMelted wax
o Tar
o Clay
o Candles
oGrease
o paraffin
o Adhesives

In this type of print, the friction ridges appear as furrows. Prints of this nature can be
photographed by angular illumination. These prints need no development.
Latent / Chance / Invisible/ Burglars Visiting Card Prints-
 It is formed by the deposition of the colorless greasy.
 This greasy substance is formed out of perspiration, dirt and oily matter from the face,
hair, skin, tools, etc which is carried by the fingers.
 Whenever, the friction skin area encounters any polished objects it leaves its
impression on the object.
 The development of latent fingerprints depending upon the surface and availability of
chemical substances. Developing method depends on several factors:-
The nature of the surface (Porous, Non- porous, rough or smooth).
 The presence of any particular contaminants
 Environmental factors
 The likely age of any evidential finger marks.
The following methods are used for developing latent Prints
 Powder Method
 Chemical Method
 Direct photography

X- ray photography
Lifting
 Chemical Powder Method
 This method is normally used on paper, glass sheets, glass tumblers and other non
absorbent surfaces.
 Types of Powder
 Colored Powders
 Magnetic Powders
 The selection of the powder depends on the background of the surface on which the
latent print has to be developed. Generally contrast color powder is used to develop the
latent prints.
 Chemical Fuming Method
 Cyanoacrylate Fuming- It is used on nonporous surfaces
 Fumes from the active ingredients of cyanoacrylate ester polymerizes on the
components of the impression’s residue creating a white impression.
Iodine Fuming- Used on porous and nonporous surfaces and unfinished wooden
surfaces.
Reacts with fatty and oily to visualize friction ridge detail.

This is a non- destructive technique
 Maximum yellow- brown details is developed upon exposure to iodine- fumes.
The developed ridge detail disappears quickly so it is necessary to take photographs
quickly.
 Ninhydrin Method
 When ninhydrin reacts with amino acids, it produced the violet compound called “
Ruhemann’s Purple / RP).
 The developed fingerprints are usually highly visible.
 It is used on dry porous surfaces ( Paper, wood, walls, cardboard).
 Can also be used to enhance prints in blood.
 Ridge details are stained a purple color.
 Heat is used to obtain catalyzed dyed complex.
 Silver Nitrate Method
 Used for fingerprints on paper
 Reacts with the chlorides, to give the insoluble silver salt, silver chloride.

• Dead Body Prints
Whenever the prints are taken from a dead body different conditions are as follow :-
 Presently dead and rigor mortis are not set in (1 to 8 hrs)
 Rigor mortis stage (8 to 24 hours)
 Decomposition stage (After 24 hours)
• Dead body in water
•Dried Fingers
• Advanced Stage of Decomposition
•Forged Finger Prints
•Fingerprint “ Forgery” is the planting of a fingerprint on a surface so that the
fingerprint appears to have been left by the finger or fingers of the person to whom it
can be identified.
• A forged fingerprint may be identified by a competent fingerprint examiner, even
though the person never touched the surface on which the fingerprints exists or
existed.
• There are three known methods by which fingerprints may be forged.
• Transfer process
• Rubber Stamp, Cast or Mould
• Photography
• In all these methods a genuine fingerprint serves as a model. The details of the
process is as under

 Damp paper method
 Kabuli method
 Lithographic method
 Film method
AFIS (Automated Fingerprint Identification System )
• The AFIS provides automated fingerprint search capabilities, latent searching capability, digital
image storage, and digital exchange of fingerprints.
• The AFIS system uses the rolled impressions or a combination of the rolled and plain
impressions of all fingers to compare the unsolved chance print database.
• Constitution of AFIS
• FACTS- Fingerprint Analysis and Criminal Tracing System.
• This part of AFIS deals with storage and retrieval of fingerprint image.
• The principal of FACTS is based on pattern recognition theory.
•CADB- Criminal Attribute Data base.
• This part of AFIs deals with storage of criminal and conviction details of culprit.
• VERIFIER- This software is used to verify the Ten digit Slips and chance prints with
database prints.
•System generate shortlist of similar prints.
• Shortlist of maximum 100 prints are generated in case of chance print and 10 prints in case of
ten digit slip.

THANK YOU
Prepared By
Sakshi Dubey
sakshikumaridubey@gmail.com

Fingerprints

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Fingerprints