consists of many microscopic scales

The ratio and quantities of

Eumalinen and Phaeomelanine

These two make up only 1% of hair structure

Phaeomelanine is resposible for red to blonde colors

Eumalinen make brown to black shades of hair

Highlighting is a cosmetic effect of lightening streaks or sections of hair

Blonding is a process that strips away original color and adds color to hair to achieve blonde appearance

Usually achieved by a mixture of bleach and a coloring agent

A low volume of peroxide (5-30%) in a cream form combined with powder bleach creates a blue paste

this is applied and left until desired amount of color is stripped from hair then rinsed out

Usually done by mixing bleach component with a alkaline solution (often ammonia)

Hydrogen peroxide breaks the sulfur bonds which releases larger amounts of sulfur

This causes hardening, loss of mass, and produces smell

minimized by using low levels of peroxide in cosmetic bleach

Temporary - lasts 1-3 washes and involves no chemical reactions with the hair

Pigments are applied to surface without penetrating further

Semi-permanent - stays in 5-15 washes usually made from vegetable dyes, mainly designed to adhere tightly to cuticle surface

Permanent - lasts indefinitely until hair grows out or chemically treated to remove color

First safe permanent hair dye created in 1907 by Eugene Schueller

Main ingredient was paraphenylenediamine

Often combines bleaching and coloring agent

Dye molecules enter the hair cortex where they react and become trapped as the cuticles close

2-[(4-aminophenyI)azo] -1,3- dimethyl - 1H- Imidazolium Chloride

C11H14N5Cl

Basic Brown 16

8-[(4-Amino - 1 Phenyl)azo] -7 - hydroxy N,N,N Trimethyl - 2 - Naphthalenaminium Chloride

Temporary skin irritation and allergies

Hair breakage

Skin discoloration

And unexpected hair color results