The effects of different colouring products on the hair• You will be looking at the effects of the

following colouring products on the hair:

• Temporary colour• Semi-permanent colour• Quasi-permanent colour• Permanent colour• Bleach.

The effects of temporary colourLarge colour

molecules coat the hair cuticle.

There is no penetration of the hair cortex.

The colour will last for only 1 or 2 washes.

The effects of semi-permanent colourSmall colour

molecules are deposited into the hair cuticle and the outer edge of the hair cortex.

The colour will last for between 6 to 8 washes.

If the hair is unevenly porous, the result may be patchy.

The effects of quasi-permanent colour

The quasi-permanent colour is mixed with a low-volume oxidant (1:2 ratio).

Different sized colour molecules enter the cortex and are oxidized by the oxidant.

Because the oxidant is mild, the colour molecules do not become very large and are gradually lost each time the hair is shampooed.

The colour is designed to fade over a period of 12 weeks.

The effects of permanent colour – stage 1The permanent

colour is mixed with hydrogen peroxide.

The strength of hydrogen peroxide used varies depending on the desired result (10, 20, 30 or 40 volume).

When mixed with hydrogen peroxide, the small colourless molecules penetrate the hair cuticle and the hair cortex.

small colourless molecules mixed with oxidant penetrate the cuticle, into the cortex

The effects of permanent colour – stage 2The hydrogen peroxide

begins to break down into water and oxygen.

The oxygen from the hydrogen peroxide joins together with and oxidises the small colourless molecules.

The oxidised molecules swell to form large, colour molecules.

The large colour molecules are unable to pass back through the hair cuticle and become trapped within the hair cortex.

small colourless molecules mixed with oxidant penetrate the cuticle, into the cortex

small molecules swell and become larger due to the nascent oxygen

The hair before bleaching Bleaching is the process of

changing the natural colour pigments in the hair so they become colourless.

The natural hair pigments are melanin and pheomelanin.

• Melanin pigments are black and brown.

• Pheomelanin pigments are red and yellow.

Natural colour pigment.

Hair prior to bleach application

The hair after bleachingThe bleach penetrates the hair cortex and oxidises the natural colour pigment so that it becomes colourless. For example, brown melanin pigments are changed to colourless oxymelanin.

Colourless, oxymelanin

Hair after bleaching