The outer layer of unprocessed human hair is composed of over lapping scales arranged in much the same way as scales on a fish. 1. On damp hair use approximately the thickness of 3 spaghetti strand. Run your finger and thumb fairly rapidly down the strands of hair from roots to ends, it will travel quite smoothly. If you do the same thing in the opposite direction from ends to roots it will feel rough, and have a bit of friction. Don't get discouraged with this method, keep trying, you will begin to feel the difference after you've done it a few times.
This test can also be performed on dry hair, but you must keep your fingers moist, this can't be overstated enough when testing on dry hair. On some hair it may feel like both directions are smooth. When this happens close you eyes and run your fingers going in each direction again. With your eyes closed you will be able to feel how one direction of the hair is slightly harder to run your fingers down smoothly.
Remember, the smooth side is going down, the rough side is going up. The smooth side is what you will work with, as this is the direction of natural growing hair. 2. Use hair the size of a pencil for this method. With the hair damp vigorously rub the hair located at the top and bottom of the hair shaft. Use two hands together in a quick rolling motion. You will find the roots will adhere much stronger than hair on the ends.
3. This test can only be preformed on bulk hair. Some naturally lighter hair colors will have darker roots and lighter ends, which can make it easy to tell cuticle direction. Don't let this fool you, you can't depend on your eyes alone to tell direction. Processed hair has a silicone layer which makes it virtually impossible to tell the actual direction by feel. Usually this silicone layer is put over hair which previously had the cuticle stripped. Silicone makes the hair feel smooth to the touch in each direction. It is still a good idea to preform these tests before install to see the actual curl pattern, as some hair changes dramatically when wet.
4. Looking through a microscope is the most foolproof way of testing for processed hair. When under a microscope you'll be able to see if the cuticle has been smoothed down, as in the picture above. Although, for the extension professional it's much easier, and faster to give the damp hair a smooth side test. It is impossible to remove all cuticles from the hair without the hair decinagrating. This is the reason it will start to tangle as soon as the coating wears off, and the remaining citicle is exposed. The silicone layer starts to wear off right away with brushing, shampoo, and general wear and tear. ****These instructions are intended solely for persons with prior knowledge of virgin hair ****