With my portrait studies, I use a pale orange ground, usually a burnt sienna thinned with turp.
Then I block in the lights and darks with an umber.
But my favorite part is getting to use that delicious cad. red light. Nose,ears and corner of eyes.
Here is the model. Tomorrow the finished painting will be posted on the About Face blog.
More Orange... "Woman on Orange" by Kerry Smith, here is an invite to his show.