fingerprint detection method ( forensic science)

Fingerprint detection

1. Fingerprint Detection NAME - JIGYANSU SEKHAR PRADHAN ROLL NO - 23S23CH05 CLASS - P.G 1 st YEAR DEPARTMENT OF CHEMISTRY GOVT COLLEGE SUNDARGARH

2. INTRODUCTION 1. WHAT IS A FINGERPRINT 2.BIOMETERIC IDENTIFICATION HISTORY 3. TYPES OF FINGERPRINT OBTAINED CHEMICAL 4.TECHNIQUES 5.CYANOCRYLATE FUMING 6.CHEMICAL DEVELOPER 7.VACCUM METAL DEPOSITION 8.APPLICATION 9.CONCLUSION

3. 1. WHAT IS A FINGERPRINT? A fingerprint is the impression left by a finger’s friction ridges upon contact with a surface. These fingerprints are a unique trademark.

4. Biometric : A human generated signal or attribute for authenticating a person’s identity Operate on Behavioral/Physical features Physical biometric features 1.Face 2.Fingerprint 3.Iris 4.Signature 5.voice 2. BIOMETERIC IDENTIFICATION

5. HISTORY Sir William Herschel who used  fingerprints  for identification on  contracts .1858

6. 1880 – Dr. Henry Faulds recognized the importance of fingerprints as a means of identification. 1888 – Sir Francis Galton published “Finger Prints” which discussed the anatomy of fingerprints and pattern types. 1897 – Sir Edward Richard Henry created another fingerprint classification system in England that included grouping fingerprint patterns according to arches, loops, and whorls. The Henry System is still in use today.

7. Types of Fingerprint Obtained: Plastic prints latentprints The name is given to the finger prints on hard surfaces which are visible .These can be photographed without the aid ofchemicals to improve visibility. Three-dimensional fingerprints left on soft surface such as wax or wet paint. Already visible,so can be photographed without the use of additional techniques. Plastic prints Patent prints Fingerprints made by the body’s oil and sweat remaining on hard surface after contact. Not visible, so various techniques are used to make them visible

8. CHEMICAL TECHNIQUES Powder Method Consist of a pigment and a binder. The pigment helps to provide contrast, whereas the binder helps the powder adhere to the print. Pigments are colloidal carbon particles, or flakes of metals including aluminum, zinc, and copper. Common binders are gum arabic, iron powder, and rosin.

9. 2. Cyanoacrylate Fuming This techniques is of particular use for rough, non-porous surfaces. The cyanoacrylate polymer is colorless, it can be visualized more easily using powder after fuming has been carried out.

10. Most commonly used chemical developer is ninhydrin. Ninhydrin was discovered in 1910 by Siegfried Ruhemann. The amino acids in the fingerprint react with ninhydrin producing Ruhemann’s purple color. 3. Chemical Developers 1,2 – diazafluoren – 9 – one ( DFO ) , make fingerprint glow in certain color of light

11. 4. Vacuum Metal Deposition (VMD) VMD is the physical process of coating evidence with very a thin metal film under high vacuum. Gold, Zinc , Silver, Tin, Aluminum, and some alloys are used to coat the substrate.

12. Applications Identify criminals in crime scenes Helps improves security Automatically recognition Enhanced device security

13. Conclusion Fingerprints offer a reliable means of personal identification. Other visible human characteristics, such as facial features, tend to change with age, but fingerprints are relatively persistent .

14. "Chemical Enhancement of Fingerprints" Forensic Magazine, www.forensicmag.com. "The Chemistry of Fingerprint Detection" "Chemical Enhancement of Fingerprints" Forensic Magazine, www.forensicmag.com. "The Chemistry of Fingerprint Detection" References