What do the different numbers on developer mean?

I went to the beauty supply store and saw that there are several volume developers and I'd like to know what the numbers mean, what they do and how they work with the color. Also, the clerk kept saying something about "taking it up" when refereing to the shade of the color.





Thanks

What do the different numbers on developer mean?
There is 10, 20, 30 %26amp; 40 volume developer.


They're different because of the amount of Peroxide in them and the more peroxide the better the faster the color will lift.





"Taking it up" thats a weird way of saying "lifting the color." If you want the color to stand out more and develop better and faster you get the bigger % of peroxide.





10= 3% Peroxide


20= 6% Peroxide


30= 9% Peroxide


40= 12% Peroxide
Reply:ok if you are asking that question you should not be dying your hair yourself. The lower the # the higher the content of peroxide (e.i lighter color). when they say taking it up means to use a higher developer in order to achive actual color not a lighter version of it. you should ask the clerk if you don't know the # developer you need for the desired color.