porous and non-porous surface

What are porous and non-porous surface?

1. DIFFERENCE BETWEEN POROUS & NON-POROUS SURFACES Presented by: Ms. Sanchita Aher M.Sc. Forensic Science, IFSM Volunteer at AFRS www.appliedforensicresearchsciences.inc

2. CONTENTS: Introduction Development of fingerprint over the surface Non – porous & Porous Surfaces Fingerprinting in both the cases Key differences between both References www.appliedforensicresearchsciences.inc

3. INTRODUCTION: Fingerprints – impression left behind by the papillary ridges and furrows present on the tip of the fingers. Significant importance as an evidence – Helps identify trait, tracing of an individual. unique and different in every individual. helps in personal identification. Minimum time and efforts helps in investigation. Permanent www.appliedforensicresearchsciences.inc Ridge Furrow Fingerprint pattern

4. DEVELOPMENT OF FINGERPRINT OVER THE SURFACE: www.appliedforensicresearchsciences.inc Fig 2. Minutiae point – Bifurcation Fig 3. Not all complete, clear and concise formation of the ridges is observed. Fig 1. Contact of fingerprint with the surface. Fig 1. Ref. www.dailymail.co.uk

5. NON – POROUS & POROUS SURFACES: www.appliedforensicresearchsciences.inc

6. CHARACTERISTICS OF FINGERPRINTING IN BOTH THE CASES: Fingerprints can be in the form of three types – www.appliedforensicresearchsciences.inc LATENT PRINT PATENT PRINT PLASTIC PRINT

7. Fingerprints in case of Non – Porous surface: The sweat and oil residues are deposited over the surface. Susceptible to get damaged. Application of powder technique. Use of contrast powders. www.appliedforensicresearchsciences.inc Fingerprint over non – porous surface.

8. Procedure to use powdered technique – www.appliedforensicresearchsciences.inc Use of feathery brush & Red Fluorescent powder Removing excess of powder to make fingerprint ridges visible.

9. Advanced effective methods – Using cyanoacrylate fuming. www.appliedforensicresearchsciences.inc Whitish coloured fingerprint pattern Fig 1. Fig 2. Fig 1. Ref. www.chm.bris.ac.uk Fig 2.Ref www.fosterfreeman.com

10. After development – www.appliedforensicresearchsciences.inc Fig. 1 PHOTOGRAPHY Fig 2. LIFTING USING ADHESIVE TAPE Fig 3. USING MAGNETIC POWDER Fig 3. Ref. How to process Latent Fingerprints using Magnetic Powder – www.youtube.com

11. Fingerprints in case of Porous surface: www.appliedforensicresearchsciences.inc The sweat and oil residues gets absorbed in the surface after the deposition. Development with chemical methods. Chemicals react with the residues. Powder methods can’t penetrate into the surface to develop the print. Chemicals: DFO/ninhydrin, iodine, silver nitrate, etc. Fingerprint over porous surface

12. DFO (1,8 – diazofluro-0-one) / Ninhydrin: www.appliedforensicresearchsciences.inc Image ref. www.sciencephoto.com

13. Iodine fuming – www.appliedforensicresearchsciences.inc Solid crystals into the chamber Yellow – brownish fingerprint pattern after the development

14. Silver nitrate – www.appliedforensicresearchsciences.inc Fig. 1. Silver nitrate solution Fig. 2. Dipping of specimen sample Fig. 3. Reddish –brown fingerprint pattern

15. www.appliedforensicresearchsciences.inc KEY DIFFERENCES BETWEEN BOTH THE SURFACES: Nature of absorbance. How long residues remain over the surface? Mechanical and chemical methods can be used in both the cases. Why to prefer powder method over non – porous & chemical methods over porous surfaces? Use of unconventional powders. Advantage/disadvantage of chemical methods. Advantage/disadvantage of powdered methods. Development of pattern

16. www.appliedforensicresearchsciences.inc REFERENCES: Fingerprints: A forensic Tool for Criminal Investigation https://www.legalserviceindia.com/legal/article-2463-fingerprints-a-forensic-tool-for-criminal-investigation Fingerprint Definition & Meaning – Merriam-Webster https://www.merriam-webster.com/dictionary/fingerprint Latent Prints – The Forensics Library https://aboutforensics.co.uk/latent-prints/ What is a Non-Porous Surface? – Chalkola Art Supply https://www.chalkola.com/blogs/ciy-create-with-chalkola/non-porous-surfaces What is a Non-Porous Material? https://www.reference.com/world-view/non-porous-material-a49974d247ab202e Comparative Study of Different Natural Products For The Development of Latent Fingerprints on Non Porous Surfaces https://www.researchgate.net/publication/306286127_COMPARATIVE_STUDY_OF_DIFFERENT_NATURAL_PRODUCTS_FOR_THE_DEVELOPMENT_OF_LATENT_FINGERPRINTS_ON_NON_POROUS_SURFACES Conventional Methods of Latent Fingerprint Development – Forensic Yard https://forensicyard.com/conventional-methods-of-latent-fingerprint-development/ BDVA – DFO https://www.bvda.com/en/dfo Fuming Cabinet, Ninhydrin Method – Fingerprint: Analysis and Understanding the Science https://ebrary.net/161565/law/fuming_cabinet

17. www.appliedforensicresearchsciences.inc THANK YOU! Like, Comment & Share