Fingerprint:
Fingerprint is the process of taking an impression of the papillary ridges of the fingertips to identify a person.
MEDICOLEGAL IMPORTANCE
- Identification by this method is absolute because
- the distribution of ridge patterns is highly divergent in different persons. So, no two fingerprints can be identical.
- the pattern remains unchanged throughout his life
- it is invariably found at the scene of crime, which can be studied
2. Fingerprints can be taken even from highly decomposed bodies.
- Fingerprint can be taken from mummified saponified bodies.
- The migration of Cl-ion can measure the age of the fingerprints.
- Millions of fingerprint can be stored so that, whenever necessary, the desired print can easily be sorted and identified for studies.
TYPES OF FINGERPRINTS
Primarily, there are 04 types of ridge patterns.
- Loops (65%)-
- Whorl (25%)-
- Arches(07%)-
- Composite (02 to 03%)
POINTS OF COMPARISON TO DIFFERENCITING FINGERPRINT:
1. Ridge pattern
2. Ridge ending
3. Ridge missing
4. Ridge breaking
5. Ridge bifurcation
6. Ridge reunion
7. Ridge gap
8. Lake Formation
9. Island Formation
10. Stud in ridge
11. Pattern of Delta
12. Pattern of Core
13. Direction of delta etc.
METHOD OF FINGERPRINTING
There are two types:
- Visible Fingerprint
- Invisible/Latent/Chance Fingerprint
Visible Fingerprint is taken in two methods
- Plain Method
- Rolled Method
Invisible Fingerprint is developed in different ways.
- When the surface is hard and non-absorbent, like glass, porcelain, wood, or metal, the developing powder is aluminum dust (gray powder) or charcoal (black powder).
- Chemicals like iodine vapor, silver nitrate, or ninhydrin are used for soft and absorbent surfaces like paper, cardboard, cloths, etc.
- Latent Fingerprints on small and moveable articles can be easily preserved after development and sent to the fingerprint lab for analysis.
- But when they are on a large, immovable surface, after developing the Fingerprint with powder, the adhesive surface of an adhesive cellophane paper is pressed on the print and then taken out. The powdered fingerprint pattern is lifted by the adhesive surface.
Nowadays, fingerprints are studied by computers. FINDER II is the digital reading system used by the FBI of the USA.