Speak to me about yellow. . . .

[Richard Budig]

I see several folks who mix a dark(er) yellow using raw umber. They start with raw umber, and bit of yellow ochre, and continue lightening with yellow ochre for a step or two, and then begin lightening yellow ochre with white. It works well, but can anyone explain why?

It doesn't seem like it would happen this way, but when you use this really "dark" version of yellow with a red, you get a really dull orange, so I guess the yellow component is there, hiding in that dark mix.

I would appreciate anything anyone can tell me about this, or any other curious mixture.