White on White is formulated to be used on all coats. It does not contain bleach or peroxide, and the optical brighteners will illuminate any color.
Gold on Gold is recommended for golden coats with darker colors intermixed, such as Belgian Tervurens, Yorkshire Terriers, and brindles.
Black on Black is for use on black or brown coats. It can also be used to deepen the color of red coats.
For salt and pepper coats, use Black on Black to deepen the dark parts of the coat, and White on White to bring out the silver strands. Apply White on White to white areas first, then Black on Black in the black areas.