The term “Resistant Hair” refers to its ability to resist penetration by water and is an indication of the condition of the outer layer of the hair (cuticle). Although hair is naturally resistant to penetration by water (hydrophobic) and coarse hair is usually more resistant than fine hair, everything we do damages the cuticle which makes the hair less resistant. Over time the ends of longer hair become less resistant than the hair near the scalp. Shampoo, styling with a hair dryer and curling iron and sun exposure all make the hair less resistant.
The term “Porous Hair” refers to its ability to absorb water and is the opposite of resistant hair. Resistant hair has low porosity (hydrophobic). Hair that is less resistant has high porosity (hydrophilic). Slick, glossy magazine paper is resistant and has low porosity. Facial tissue is less resistant and has high porosity.
Resistant hair is more difficult to color or perm because it resists penetration, but resistant hair is often used as an excuse when a color or perm fails to achieve the desired results. Although gray hair is often believed to be resistant, gray hair is no more resistant than the pigmented hair on the same head. The structure of gray hair is identical to the structure of pigmented hair but requires more color simply because it is has no color.
A deposit color formula on gray hair must be a level six or lower and contain all three primary colors in the following proportions; three parts yellow, two parts red and one part blue to achieve a natural looking hair color.
Dirty, dry hair is more resistant that clean, damp hair. Shampoo and towel dry the hair prior to the haircolor application. Water swells the hair and draws the color into the hair due to hydrogen bonding