Hair Coloring Dallas
Hair Coloring Agents
Temporary Hair Color
Temporary dyes are derived from the textile industry and are used more for fun or for a party, as they are washed out with the next shampoo. These dyes can also soil clothing or bedsheets and caution should be exercised.
A gradual change from gray to brown or black can be witnessed with the application of metallic salts to the hair. The colorless lead salt converts to brownish oxides and sulfides. As the dyes precipitate on the outside of the cuticle, they can render the hair dull and brittle. The smell of sulfides that emanate from the dye can also be unpleasant. Also, the metallic coat over the cuticle prevents penetration of permanent waves or permanent color.
Henna provides temporary coloring that requires 4 to 6 shampoos to remove. Given the high incidence of asthma, this product has not been widely adopted. It does not preclude permanent waving.
Low-molecular weight dyes like nitroaminophenols and aminoanthraquinones can penetrate the cuticle by virtue of their small size. Because they do not contain hydrogen peroxide, they cannot lighten hair. These dyes are washed out with shampoo after 4 to 6 times and can be used at home for someone contemplating a change of hair color but is undecided.
The most common type of hair coloring is permanent or oxidative hair color. Primary intermediates (“para” dyes) are combined with hydrogen peroxide to yield imines. The imines are then combined with couplers to create indo dyes. After the reaction, the molecules are too large to pass out of the cuticle making the change permanent.
To lighten the hair color, a two-step process must be undertaken in which the hair is first bleached with hydrogen peroxide then recolored with a toner. Individuals who have undergone this two-step process are ineligible for permanent waves. After coloring, an acidic pH shampoo should be used to help the cuticle close.