Techniques to Identify Hair/Fibers

Hair: The most basic form of identifying hair samples is looking at different samples under a lightened microscope and comparing it to various originals. For example male hair usually looks alike so if you were able to math an unknown sample to an Asian hair sample then you would be able to conclude that your suspect is Asian. However, there are many things that makes hair analysis unreliable for example if you use any type of bleach, shampoo, or hair dyes in your hair it can change the way that it looks under to microscope therefore causing a negative test for any forensic scientist. techniques
http://www.fbi.gov/hq/lab/fsc/backissu/july2000/deedric1.htm


Fibers: Almost the same technique is used when identifying fibers. In order to find the identity of a fiber you would need to take a small piece of the fiber and look at it under a microscope and then compare it to original samples of fibers to find a match. Another method would be the stain test which proves if a fiber is hydrophobic, meaning it will not absorb water, or hydrophilic, meaning it will absorb water. A density test can also be used to see if the fiber will either float or sink, however, fiber blends can skew the results.

http://www.associatedcontent.com/article/80155/textile_fiber_identification_pg2.html?cat=51