1. Fibers and Threads

2. Cloth can yield: class &individual characteristics. Matching fibers involves comparing: type of fiber, color, type of dye,production method.

3. Classification of Fiber Until 19 th C. only natural fibers used to make clothing Mineral – think earth… glass, asbestos Animal – silk, wool, fur Vegetable (plant) – cotton, linen, hemp Synthetic – rayon, nylon, acetate –Currently 50% all fibers are synthetic

4. Many different natural fibers that come from plants and animals are used in the production of fabric. http://www.fireflydiapers.com/articles/diaperarticle_naturalfibersabsorb.htm Cotton fibers are the plant fibers most commonly used in textile materials The animal fiber most frequently used in the production of textile materials is wool, and the most common wool fibers originate from sheep. Natural Fibers

5. More than half of all fibers used in the production of textile materials are synthetic or man-made. Nylon, rayon, and polyester are all examples of synthetic fibers. Cross-section of a man-made fiber Synthetic Fibers Fibers under a microscope

6. Synthetic Fibers: Petroleum is the basis for these fibers, and they have very different characteristics from other fibers. Monomers are joined together to form polymers. The fibers produced are spun together into yarns. They have no internal structures, and under magnification they show regular diameters.

7. Comparison of Natural and Synthetic Fibers Visual Diagnostics of Some Common Textile Fibers under Magnification

9. Fibers can be twisted (spun) into: any length, thick or thin, loose, or tight. A blend can be made to meet different needs such as resistance to wrinkling. Fibers can be woven into fabrics. –Threads are arranged side by side (the warp). –More threads (the weft) then are woven back and forth crosswise in one of a number of different patterns through the warp.

10. Weave Patterns

11. What are some tests that will help to identify a fiber?

12. Burn Test Burning a fiber can give you hints to the type of fabric based on what you see: Characteristic odors Residues Beading Smoke or smolder? Flame or no flame?

13. Solvent/Solubility Test Can the fiber dissolve in certain solvents? Often the following solvents are used to help ID a fiber: HCl NaOH Bleach Acetone Dry-Cleaning Solvent

14. Stain Test (They show these types of tests in laundry commercials all the time.) Will blood stain the cloth? Will blood ‘bead’ off? Is this lipstick?

15. Microscopic Tests What can you see using the microscope? Weave Braids Folds & Twists Translucency Fraying Was it cut or ripped?

16. Collection Methods The two most common ways to collect fiber evidence are: #1. The Tape Method… (you probably have done this before when you have held a critter and they have left half of their white fur on your black shirt.) #2. Sweeping/Vacuuming Method: work well but collects LOTS of other debris.

17. So… Where else besides clothing do you look for fibers? Rugs Drapes Couches Pillows Cars

18. You can really learn a lot of stuff from fiber and other trace material.

19. Stuff like: Skin cells on ropes… (kidnapping, murder, suicide?) Fibers on duct tape…. (kidnappers’ tool of choice…) Rope characteristics: # of strands, twist direction, weave pattern, color, diameter, weight Soil, rocks, debris give possible location Building materials Wood & plant material