1. Hair Colouring
Hair Colouring is the process of adding
colour to the natural hair colour. It is used to
disguise or cover over white hair, or to
enhance and change the natural hair colour.
Hair Colouring
The natural pigments of hair are found in the
cortex; outermost layer of the hair-shaft- the
cuticle-that covers and protects the cortex, is
translucent, therefore it allows us to see
through the hair’s natural colour. Eumelanin
is the black and brown pigment, while
phaeomelanin is the pigment responsible for
blond and red.
Product Available to Dye Hair
Temporary colour: this type of colour is found mainly in sprays, gels, water rinses and some
colour shampoos. This colour contains large colour molecules which are too large to penetrate the
cuticle layer of the hair, and it doesn’t contain ammonia, which is used to open the hair cuticles,
allowing the colour molecules to penetrate inside the hair. This type of colour will only last one
wash.
Semi –permanent colour: this type of colour will last between six to eight washes, depending on
the natural hair colour and the tone of the colour used. With eight shampoos the colour will fade.
This type of colour contains a mixture of sizes of coloured molecules, and as it is slightly alkaline
the cuticle scales will open, thus allowing the product to enter the cuticle: the smaller the
molecules, the farther they will travel. So as the hair is shampooed each time, the large molecules
will wash out but the smaller molecules will remain, enabling the colour to last longer.
Permanent colours: these tints, also called oxidation dyes, require the addition of hydrogen
peroxide, otherwise they will not work. The small colourless molecules within the tint enter the
cortex. Once inside, the hydrogen peroxide activates them into joining together to form large
coloured molecules which then become trapped within the cortex. This process can take anything
from thirty minutes to sixty minutes, depending on the product that you are using. If this product
is taken off too soon, it will become semi-permanent.
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