the effects of different colouring products week2
TRANSCRIPT
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 colour
Large 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 colour
Small 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 1 The 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 2 The 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
colourles
s
molecule
s mixed
with
oxidant
penetrate
the
cuticle, in
to the
cortexsmall
molecule
s 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 bleaching
The 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