HI all, since black i very dark its hard to know the wash, suppose I should use and lightcolored wash?

You might want to start with a dark gray as the base color then shade in black or even Prussian blue. Add flesh color to the black for highlights.

You can start out with base of black with a good portion of dark blue or blue black in your base mix. You gotta do something to insure that you have the ability to place shadows.

For highlights, you can put down and blend progressive layers of very thin base + light blue + purple. Adding more light blue as you go. As a final highlight I have seen white used effectively as well. But, I have not tried that.

Because you have used a Black blue base, a pure black shadow will now work. Blend in to highlights.

Sounds simple, huh? It isn't for me but it works pretty well.