July 15, 2008
OOPMAHS .... OOPMAHS ! One of the most thorough Segments on the subject
The average hair density is about 2,200 hairs per square inch. Hair with high density ( thick or dense hair) has more hairs per square inch. The average head of hair contains about 100,000 individual hair strands. the number of hairs on the head generally varies with the color of hair. Blondes usually has the highest density and redheads ( boo-hoo) have the lowest.
POROSITY: If only I could stress the importance of this characteristic, I would be able to access some of your hair so much easier. Porosity is the ability of the hair to absorb moisture. The degree of porosity is directly related to the condition of the cuticle layer. Healthy hair with a compact cuticle layer is naturally resistant to penetration. Porous hair has a raised cuticle layer that easily absorbs water.
Hair with low porosity is considered resistant (see photo) . Chemical services performed on hair with low porosity require a more alkaline solution than those on hair with high porosity. Alkaline solutions raise the cuticle and permit uniform saturation and processing.
Hair with low elasticity is brittle and breaks easily. Hair with low elasticity may not be able to hold the curl from wet setting, thermal styling ( curling irons ) or perms. Hair with low elasticity is the result of weak side bonds that usually result from over processing. Chemical services performed on hair with low elasticity require a milder solution with a lower pH, that solution minimizes damage and helps prevent additional over processing.
Check elasticity on wet hair by taking an individual strand from four different areas of the head ( the front hairline, the temple, the crown, and the nape). Hold a single strand of wet hair securely and try to pull it apart ( see photo - elasticity). If the hair stretches and returns to its original shape without breaking, it has normal elasticity. If the hair breaks easily or fails to return to it original length then it has low elasticity.
Whew! that was a mouthful and a page full but its something I have wanted to get said. So I am glad it finally is. This is just the beginning of how the hair structure pertains to shampoos and hair care products, which is all forth coming so just hang on - I hope you will like this series, lots of facts - lots of science .... KC