The levels of decolorazation. (Bleaching hair)
Every hair color has a level, 1 being the darkest and 10 being the lightest. Every color has an underlying tone, black and brown has a red tone. When you bleach hair you are showing the underlying pigment, which is why someone with black or brown hair bleaches it and it can turn out to be orange.
There are four devolpers we use to bleach hair, a 10, 20, 30 and 40.
10 = lifts one level
20 = lifts two levels
30 = lifts three levels
40 = lifts four levels
NEVER USE A DEVELOPER OVER 40.
Okay, let’s say we are starting with a level 3 hair color, and we use a 40, we will end up at a level 7, and it won’t lift above a 7.
If you want to go lighter, you have to start at the level 7 and use a 30 to reach 9 or 10. (10 is hard to achieve)