DEVELOPMENT OF FINGERPRINTS

development and preservation of latent fingerprints

1. Unit 3: Development of Fingerprints Course Name: Forensic Dermatoglyphics Course Code: FSC204A31 Lecture 1 Lesson 1

2. TYPES OF FINGERPRINTS 1. Latent fingerprint - earlier stated was invisible to the eye since just oils and perspiration. 2. Visible Prints- made by fingers touching a surface after ridges have been in contact with colored material: BLOOD, PAINT, GREASE, INK Plastic Prints -are ridge impressions left in soft material- putty, wax, soap, or dust.

3. Latent fingerprints – fingerprints that are invisible to the naked eye and caused by the transfer of oils and other bodily secretions onto a surface. They can be made visible by various different methods

4. Patent fingerprints – visible prints left on a smooth surface when blood, ink, or some other liquid comes into contact with the hands and is then transferred to the surface

5. Plastic fingerprints – actual indentations left in some soft materials such as clay, putty, wax, or dust.

6. Types of Surfaces NON-POROUS GLASS, MIRROR, PLASTIC, PAINTED SURFACES ENHANCE WITH SUPER GLUE and/or POWDER

7. Types of Surfaces POROUS PAPER, CARDBOARD, CLOTH ENHANCE WITH CHEMICALS

8. Types of Surfaces SEMI-POROUS polished surfaces Can absorb and can resist also

9. Types of Surfaces TEXTURED SURFACE

10. https://www.youtube.com/watch?v=fbTiLDJCQ0o

11. FACTORS AFFECTING FINGERPRINTS Age – thinner epidermis, flattening of dermal papillae, creases, etc. Fine ridge structure – less skin contact leads to a spotty appearance. Stimuli – sweating can be due to warmth, exertion, fever, drugs, anxiety, tension, pain, or spicy foods. Occupational and medical condition – teaching, and other positions in which a person handles or shuffles papers, can cause fine ridge structure.

12. FACTORS AFFECTING FINGERPRINTS (CONTINUED) Transposal factors Receiving surface texture Contaminants on the hands Contaminants on the receiving surface The manner of contact The amount of pressure Environmental factors Temperature Humidity Handling

13. Constituents of sweat residue

14. Glands responsible for the production of sweat Eccrine Apocrine Sebaceous glands Each gland contributes a unique mixture of chemical compounds

15. Apocrine Sweat Glands Found in the axillary (arm pit) and anogenital areas Larger than eccrine glands Ducts empty into hair follicles

16. Apocrine Sweat Gland Secretion contains same component as sweat plus fatty substances and proteins Odorless when secreted, but when decomposed by bacteria on skin, turns musky – basis of body odor Sometimes has a milky or yellowish color

17. Eccrine Glands Eccrine glands are present all over the body without any exceptions and thus play an important role in fingermark composition. The main constituent of their secretions is water (99%), but many other inorganic and organic compounds have also been identified.

18. Eccrine Sweat Glands Most numerous, widely distributed – especially abundant on the palms, soles of feet, and the forehead

19. Eccrine Sweat Glands Simple, coiled tubular gland Secretory part lies coiled in the dermis Open to skin surface by ducts (pores)

20. Eccrine glands: Are smaller diameter (50 – 100 μ m) Are active from birth ( Apocrine glands become active only at puberty) Produce a sweat that is free of proteins and fatty acids

21. Sebaceous (oil) glands Simple alveolar glands Found all over the body – except palms and soles of feet Small on body trunk and limbs, but large on face, neck, and upper chest

22. Sebaceous glands found all over the body except on the hands and feet secrete sebum- a major component of fingermark composition hands and feet are free from sebaceous glands sebum is transferred onto fingertips only after contact with other parts of the body

23. Sebaceous (oil) glands Produce oil (sebum) Lubricants and softens skin and hair Kills bacteria Most with ducts that empty into hair follicles Glands are activated at puberty Stimulated by hormones

24. Sweat average quantity of secretions produced during a typical 24-hour period varies between 700 and 900 grams The pH of sweat has been reported to vary from 7.2 (extracted directly from the gland) to 5.0 (recovered from the skin surface at a low sweat rate) to between 6.5 and 7.0 (recovered from the skin surface at a high sweat rate.

25. The amount of sweat produced depends upon our states of emotion and physical activity . Nerve stimulation Exercise

26. Function of sweat Thermoregulation which is the principle function of sweat. Sweating allows the body to rid itself of excessive heat production through the evaporation of water which brings about cooling of the body.

27. Characteristics Composition of the primary secretion is very similar to that of plasma except that it does not contain plasma protein: PH: 4.5 – 7.5 Na+ : 30-70 mg ( less). K+ : 0-5mg (same). Cl- : 30-70 mg (less) . Urea: 4-6 times higher than in plasma. Lactic acid : higher than in plasma specially in athletes. [Glucose] in a very small amount

28. Composition of Sweat Inorganic ions (Na+, Cl-) Proteins, amino acids Lipids Water water and other components in the fingerprint will evaporate or degrade rather quickly, it is the lipids (fats and oils) and amino acids that allow fingerprint residues to last long enough for collection.

29. Lipids also called fats or oils represent one of the four major classes of biological molecules. Lipid molecules are all based on the presence of fatty acids, which are long carbon tails (16-20+ Carbons long) with a carboxylic acid (-COOH) group at one end. Iodine binds to the lipids in the print.

30. https://www.youtube.com/watch?v=XLvZkx7HEEA&feature=youtu.be

31. Amino Acids the building blocks of proteins the biomolecules that make up the muscles and enzymes in our bodies serve as one of the more important biochemical molecules There are 20 common amino acids, all of which contain the same core structure Ninhydrin reacts with amino acids

32. https://youtu.be/fF_v-MymoOk

33. Sodium Chloride (water Soluble) silver nitrate

34. Aging of Latent Print Residue composition of latent print residue can change dramatically over time Studied by U.K. Home Office Scientific Research and Development Branch and Central Research Establishment.

35. In short - Conclusion Fingerprint residue Chemistry is complex An emulsion of water, organic and inorganic compounds Is also referred to as a three dimensional matrix

36. https://www.youtube.com/watch?v=66p-XA8Qi0o