FINGERPRINTS I History of Fingerprints

1. FINGERPRINTS I History of Fingerprints 1. The first systematic attempt at personal identification was introduced by Alphonse Bertillon in 1883.

2. His system relied on a detailed description of the subject combined with full length and profile photos and a system of 11 precise body measurements (known as anthropometry).

3. These included height, reach, head width, length of left foot. His premise was that no two people could have exactly the same measurements.

4. 2. There is evidence that the Chinese used fingerprints to sign legal documents 3000 years ago. • 3. In 1892 Francis Galton published “Finger Prints”.

5. He assigned fingerprints into 3 pattern types – loops, arches, and whorls. He also demonstrated that no two prints are identical.

6. 4. Sir Edward Richard Henry developed a classification system that organized them in a logical and searchable sequence. Currently the FBI has the largest collection of fingerprints in the world.

7. 5. The admissibility of fingerprints was challenged in the case of United States v. Byron C. Mitchell. The defense claimed the individuality of fingerprints cannot be scientifically proven.

8. The judge ruled 1) human friction ridges are unique and permanent and 2) human friction ridge arrangements are unique and permanent.

9. II FUNDAMENTAL PRINCIPLES OF FINGERPRINTS • A – First Principle: A fingerprint is an individual characteristic, no two fingers have yet been found to posses identical ridge characteristics.

10. 1. The individuality of a fingerprint is not determined by its general shape or pattern but by careful study of its ridge characteristics (minutiae).

11. These characteristics include bifurcations, ridge endings, short ridges, islands, enclosures, ridge crossings. It is the identity, number, and relative location of these characteristics that impart individuality to them.

12. There may be 150 individual ridge characteristics on the average print.

13. If two prints are to compare, they will have to reveal characteristics that not only are identical but have the same relative location to one another in a print.

14. In court a point-by-point comparison must be demonstrated by a fingerprint expert.

15. How many characteristics must match? Numbers range from 8 to 16 are generally acceptable. It is generally left up to the court in individual cases.

16. B. Second Principle: A fingerprint will remain unchanged during an individuals lifetime. • 1. fingerprints are a reproduction of friction skin ridges found on the palms and soles of the feet.

17. These ridges help grasp and reduce slippage. Friction skin has a series of hills (ridges) and valleys (grooves). It is the shape and form of these ridges that you see as a fingerprint impression.

18. 2. Skin is composed of layers of cells. Those nearest the surface make up the epidermis. Under the epidermis is the dermis. Between the two layers are separated by a layer of cells called the dermal papillae.

19. It is this layer that determines the form and pattern of the ridges on the surface of the skin. Once the dermal papillae develop in the human fetus, the ridge patterns will remain unchanged throughout life.

20. 3. Each skin ridge has pores that are openings for sweat glands. Once the finger touches a surface, perspiration along with oils on the skin are transferred onto surface leaving a fingerprint.

21. Prints deposited in this way are invisible to the eye and are commonly called latent prints.

23. Can acid eat away fingerprints?

24. No. John Dillinger tried but to eliminate them you have to go down 2 mm beneath the surface.

25. It is almost impossible to obliterate all ridge characteristics and the scars make new identification easier.

26. C. Third Principle: Fingerprints have general ridge patterns that permit them to be systematically classified. All fingerprints are divided into 3 classes on their general pattern; loops, whorls, and arches.

27. 60-65% of the population has loops. • 30 – 35% have whorls. • 5% have arches.

31. In the Loop pattern there are two focal points: the Core, or the center of the loop, and the delta. The Delta is the area of the pattern where there is a triangulation or a dividing of the ridges.

32. A Whorl pattern will have two or more deltas.

33. The Arch pattern has no delta or core

35. PRESERVATION of PRINTS 1. First a photograph must be taken. These are specialty cameras made for taking photos of prints.

36. 2. Once photos have been secured one of two procedures is to be followed. a. if the print is on something small enough to be moved it is covered with cellophane taken back to the lab.

37. b. If it is on something to large to move the prints must be lifted. The print is dusted with powder than tape is applied over it. When the tape is removed the powder shows the shape of the print.

38. DIGITAL IMAGING for FINGERPRINT ENHANCEMENT 1. Digital imaging software can be used to enhance prints that are not in perfect conditions.

39. 2. Digital imaging is the process by which a picture is converted into a digital file. The image produced from this is composed of only black and white elements and referred to as grayscale images.

40. The picture is composed of pixels. • Each pixel is assigned a number according to its intensity ranging from 0 (black) to 255 (white).

41. Once an image is digitally stored, manipulation of the picture is done with computer software that can change the numerical value of each pixel.

42. Resolution refers to the degree of detail that can be seen in a image. Resolution can be defined in terms of dimensions (800x600). The larger the dimensions the closer to a real-world image the picture will appear.

43. The digital image may be modified by changing the brightness, increasing contrast, filtering to reduce hard edges, other filters can be used to remove color. (ex. Prints found on money)

44. Another important and useful digital tool is the compare function. This feature allows the examiner to compare features and zoom in on certain parts.

45. Fingerprint Test ?