non pregnancy related. if I want to go from blonde to black color, what volume developer do I need…

20

Depends on your natural color. But since you are only depositing color, you can use a 10v developer.

@p0790, @sixthontheway my natural color is dark brown but now my hair is bleached blonde and I want to go jet black

I would say a 20 developer. It's not too strong or to weak just right. @momtobeagain

You'll want to use a filler to get some pigment in there first. Otherwise your bleached out hair is going to suck up the color where it is the most dry.

@sixthontheway, thanks! yes Im definitely getting a filler. :)

@benz305, thanks! :)