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A Complete guide to Fingerprint Analysis

What are Fingerprints?

Impression left by the friction ridges on the finger are known as Fingerprint.A Fingerprint consists of ridges and furrows in patterns,which make them unique.

Origin

  • Edward Richard Henry (1850-1931) –He devised the fingerprint classification formula, recommended the use of mercury based and graphite based powders. 
  • Sir William Hershel,1856 -The first to use fingerprints An English Chief Magistrate in India who used prints on native contracts. 
  • Dr.Henry Faulds,1880 -Notices fingerprints on pre-historic pottery 
  • Sir Francis Galton,1888 -Sir Francis Galton, a British anthropologist and a cousin of Charles Darwin, began his observations of fingerprints as a means of identification in the 1880’s. In 1892, he published his book, “Fingerprints”, establishing the individuality and permanence of fingerprints. The book included the first classification system for fingerprints.

Types of prints

  • Latent print
  • Patent print
  • Plastic print

Latent print

It is invisible to the eye produced due to the deposition of oils and perspiration.

Patent print

It is visible on surface after ridges have been in contact with colored material: blood,paint,ink,.

Plastic print

Impressions left on soft material: putty, wax, soap, or clay,.

Collection methods

Latent print

Use alternative light source(UV light),High Definition Photograph,tape lifting method,chemical fuming methods(cyanoacrcylate, ninhydrin, silver nitrate)

Patent print

Use alternative light source(UV light),High Definition Photograph,tape lifting method.

Plastic print

Casting methods

Collection of Fingerprint from the dead

Casting methods-For skin that’s badly deteriorated, it may be possible to use silicone putty to make a casting that captures the detail of the fingerprint ridges. Those impressions can then be photographed and used in identification. Most sensitive to taking an impression, even under only moderate pressure against the mold. 

Thanatopractical  processing– fluid is extracted from other parts of a body’s remains is used to restore tenseness and volume to the fingers in order to plump them for printing.

In case of rigor mortis, straighten the fingers. This can be accomplished by pressing down on the middle joint of the finger. Dust the fingers and palms with fingerprint powder and lift the prints with tape or rubber lifters.

Surfaces

Porous: Absorbent surfaces such as cloth,paper,. 

Non porous: Non absorbent surfaces such as glass,plastic,.

Principles of Fingerprint Analysis

1. A fingerprint is an individual characteristic because no two fingers have yet been found to possess identical ridge characteristics.

2.   A fingerprint will remain unchanged during an individual’s lifetime. 

3.  Fingerprints have general ridge patterns that permit them to be systematically classified.

Fingerprint Analysis

Types of Ridge patterns

Loops

Loop must have one or more ridges entering from one side of the print, recurring and exiting from the same side. 

It should have one core and one delta If loop 

-Opens towards little finger= ulnar loop 

-Opens towards the thumb= radial loop

These patterns are named for their positions related to the radius and ulna bones, i.e. the bone the loop opening is facing towards.

Whorls

  • Plain Whorl
  • Central pocket loop whorl
  • Double loop whorl
  • Accidental whorl

All whorl patterns have type lines and a minimum of two deltas. 

Central pocket loop whorl have at least one ridge that makes a complete circuit. 

Ridge may be spiral, oval or any variant of a circle.

Double loop whorls (Twin loop)are made up of any two loops combined into one print.

Accidental whorls contain two or more patterns which does not clearly fall under any of the other categories.

Arches

  • Plain Arch-Ridges enter on one side and exit on the other side.
  • Tented Arch-Similar to the plain arch, but has a spike in the center.
Arch patterns do not have Type lines,Core and Delta

Ridge Characterstics

Class Characterstics

Type Lines-Pattern area of the loop is surrounded by two diverging ridges known as type-lines.

Core-Core is defined as the innermost turning point where the fingerprint ridges form a loop.

Delta-Delta is defined as the point where these ridges form a triangular shape.

Individual Characterstics

Bifurcation(Fork)- A ridge diverging into two parallel ridges,forming a fork shape.

Spur (Hook)-A ridge diverging from the main ridge to form a hook.

Enclosure(eye)-A ridge divides into two and the two divided ridges immediately converge into a singe ridge,forming an eye shape.

Dot-A very small fragment found inbetween the pattern.

Trifurcation- A ridge dividing into three parallel ridges.

Bridge- Two ridges connected by a bridge.

Ridge Counting

The number of ridges intervening between the delta and the core is known as the Ridge Counting.

  • Ridge counting is performed on loop type pattern. 
  • If there is a bifurcation at the exact point of coincidence, two ridges are counted. 
  • If there is a bifurcation of a ridge exactly at the point where the imaginary line would be drawn, two ridges are counted. 
  • Fragments &dots are counted if they appear as thick as the neighbouring ridges. 
  • Ridges, which run close up to without meeting the line, are not counted. 
  • Where the line crosses an island, both sides are counted.

Ridge Tracing

  • The course of the lower ridge of the delta, is followed and it will be found either to meet or to go inside or to go outside the corresponding ridge of the delta. 
  • If the course of the ridge ends abruptly, the course of the next ridge below it is to be followed. 
  • In case of bifurcating ridge the lower line of bifurcation should be followed. 
  • When the traced ridge meets the corresponding ridge of the right delta or goes inside or outside, with not more than two ridges intervening between them, the Whorl is specialised as Meeting(M). 
  • When the ridge goes inside and there are three or more intervening ridges, it is specialised as Inner(I). 
  • When the ridge goes outside and there are three or more intervening ridges, it is specialised as Outer(O).

Database

Fingerprint Analysis and Criminal Tracing System (FACTS) & Aadhar 

The computer uses an automated scanning device to convert the image of a fingerprint into digital ridge characteristics. (image processing and pattern recognition techniques) 

Holds information of class characteristics, individual characteristics , minutiae location, direction, ridge count, density, type of print,. National crime records bureau and Central finger print bureau hold access to FACTS.

Applications

  • Biometric security 
  • Identity recognition in mass disasters 
  • Conducting background checks 
  • Criminal investigation

Recent Trends

Determining use of illegal drugs: 

Researchers from the University of Surrey in England have developed a method to test the residue left in a fingerprint for cocaine using mass spectrometry. 

Fingerprint Molecular Identification (FMI) technology to identify gender, narcotics and nicotine: 

North Carolina’s ArroGen Group has developed FMI technology, again using mass spectrometry, to identify gender biomarkers, as well as metabolites of nicotine, heroin, methamphetamine, marijuana, temazepam, ecstasy and even some legal medications. 

Developing Technique Bacteria:  

Certain bacteria, for example acinetobacter calciacatieus, can be used to develop prints on valuable oil paintings, without harming the painting in the process.  The bacteria in a nutrient gel are pasted onto the surface of the painting, making the print visible as they multiply.  The gel can then simply be wiped off, leaving the painting unaffected. 

Autoradiography:  Radioactive atoms are incorporated into the fingerprint by placing the piece of fabric into a container containing radioactive gases, such as iodine or sulphur dioxide, at a humidity of less than 50%.  The fabric is then put into contact with photographic film, and the radioactive atoms cause a picture to become clear.

The Identification of Prisoners Act 1920

Section 1: An act to authorize the taking of measurements and photographs of convicts and others. 

Section 2: Definitions “ Measurements” include Finger impressions and foot print impressions 

(a) “Police Officer” means an officer in charge of a Police Station, a Police Officer making an investigation under chapter XIV of the Code of Criminal Procedure, 1898 or any Police Officer not below the rank of Sub – Inspector. 

(b) “Prescribed” means prescribed by rules made under this Act.

Section 3: the SHOs and investigating officers are empowered to take the finger prints of every person who has been convicted of any offence punishable with rigorous imprisonment for a term of one year or upwards or of any offence which render him liable to enhanced punishment on a subsequent conviction.

Section 5: A First Class Magistrate can direct to give the FPs of any person arrested in or for the purposes of any investigation or proceeding.

Collection of Fingerprint for comparison

Under the provisions of 73 IEA and Section 5 & 6 of Identification of Prisoners Act, the law enforcing authorities and courts have been empowered to take finger prints of a person for the purpose of investigation or identification.

On refusal,

Section 6 of Identification of Prisoners Act:If any convict resists to give finger prints necessary measures should be to taken to secure his finger prints.If he still refuses, he can be charged u/s 186 IPC and he is liable for punishment.

Expert Testimony

In 1899 amendment was made to Evidence Act, Section 45 & 73 and evidence of finger Print Expert was given a statutory recognition. 

Section 45 of IEA, when the court has to form an opinion upon a point of foreign law, or of science or art or as to identity of handwriting or finger impressions, the opinion upon that point of persons specially skilled in such foreign law, science or art or in questions as to identity of handwriting or finger impressions, are relevant facts. Such persons are called Experts.

Under Section 293 Cr.P.C.Report submitted by Director, FPB as Expert opinion may be used as evidence.The court may, if it thinks fit, summon and examine any such Expert.If the Director, FPB is summoned by a court and he is unable to attend personally, he may, unless the court has expressly directed him to appear personally, depute another Expert who is conversant with the facts of the case.

Palm prints comes within the section of 45 IEA and opinion of Experts as to identity or non-identity of palmer impressions are admissible in court.

Section 60 of IEA, if oral evidence refers to an opinion or to the grounds on which that opinion is held, it must be the evidence of the persons who holds that opinion on those grounds (i.e. Expert need not be present in the court).

Under section 20 (b) of Cr.P.C. any document produced before the Magistrate on which prosecution to rely, provided that Magistrate is satisfied that any such document is voluminous, he shall, instead of furnishing the accused with a copy thereof, direct that he will only be allowed to inspect it either personally or though pleader in the court.

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