teach me about the hair color theory
Answers
Porosity
One of the first things to consider when planning a color service is the degree of porosity
of the hair. Porosity is defined as the hair's ability to absorb moisture. It is not to be
confused with hair texture. These are two different terms that refer to two different
aspects of the hair.
The amount of porosity is to be analyzed and placed into one of three categories.
Cosmetic Art Science terms these categories as “degrees of porosity”.
The degrees of porosity are: low, average and high.
There are clinical techniques to determine hair porosity. During testing you will be using
your sense of touch to categorize the client's hair.
You will test the four main areas of the head:
1. the front hairline
2. the temple
3. the crown
4. the nape
Create a small strand of just a few hairs and hold it perpendicular to the head. With the
opposite hand, grasp the hair strand using your thumb and forefinger then slide your
fingers slowly and gently from the ends to the scalp. You are feeling for the amount of
roughness of the hair cuticle.
The smoother the hair feels the lower the degree of porosity that is present. The rougher
the hair feels the higher degree of porosity that is present.
Low Porosity: The hair feels smooth when tested.
Hair that has a low degree of porosity has a lessened ability to absorb moisture and is
considered resistant to chemicals. Hair that has a low degree of porosity might take
All colours found in nature are a mix of the three primary colours: blue, red and yellow. These three pigments produce every known colour in the world, except black and white.
Our skin and hair colours are made up of various combinations and proportions of blue, red and yellow colour molecules.
Blue is the only cool primary colour – red and yellow are warm.
Hair Shaft
Pigments that colour our hair are found in the cortex
Primary colours in our hair vary in molecular size and pigment weight – and this is important to understand in hair colouring. Blue has the largest molecular size and pigment weight, followed by red and then yellow.
In the hair shaft, blue molecules (being the biggest) sit closest to the cuticle and blue is the easiest pigment to remove during colouring. Red molecules are found deeper in the cortex and are harder to remove than blue. Harder still are the yellow molecules, which sit deepest in the cortex. This is why red and yellow are harder colours to remove during the lightening process, as these pigments are deeper inside the hair shaft.
To remove red and yellow pigments, the hair shaft needs to be expanded large enough and for long enough during colouring to allow oxidation to dissipate the molecules into the air.