Each Colour Developer has a different Lightening value or strength, to suit every individual Hair Colour.
Its simple, the first number on the Developer represents the level it will lift your Natural Hair Colour.
For Example:
No lift deposits Colour, only ideal for going Light to Dark.
20 Volume will lift your Natural Hair Colour up to 2 levels.
30 Volume will lift your Natural Hair Colour up to 3 levels.
40 Volume will lift your Natural Hair Colour up to 4 levels.
Or if you refer to Developer as Peroxide the levels are:
20 Volume Developer – 6% Peroxide
30 Volume Developer – 9% Peroxide
40 Volume Developer – 12% Peroxide
Conditioning Activator – 7.5% Peroxide
