Dealing with previously colored hair???

Question

What must you consider when it comes down to the underlying pigment and the contributing pigment?

Correct me if I am wrong. under pigment lies under the natural hair, and the contributing pigment is the stages the hair goes through as the color processes?

And my second question:

For example, if your natural hair color is dark brown and you brought it to a medium brown, waited a few months and decided that you would like to bring your hair up to a medium blonde, what factors must I consider when dealing with the under pigment, and contributing pigment? do i need to neutralize the medium brown before I work with the medium blonde?

Answer 1

you are correct on underlying and contributing pigment. second q: I would do the blonde first, and then neutralize the blonde with a toner. I feel that would be the easiest to formulate