This is the Umber Layer 1 or Rubout Technique:
After applying a coat of Bruno Imprimatura I applied a technique I borrowed from Frank Covino (The Rubout) so with a rag, fingers and kneaded eraser I sculpted with light the forms to bring out the 3d effect in them. In this step I am trying to model surfaces so not much worry about textures, the next layer will take care of that.
1. Next time use a lighter value for the Rubout coat mix.
2. Next time remove more of the umber layer on areas where light colors and colors like blue, violet and pink are going to be.