Pastel Technique: Using Toned Paper
This is a Wallis grayish brown toned sanded pastel paper. I felt that the brown tone will help fill the ground beneath the grasses of the Irish landscape photo (see below). This is a sketch in vine charcoal to capture the basic planes and lines in the landscape.
Here is the photo. What is interesting about this composition is the variety of planes, from the distant mountains through the swaths of field up toward the foreground, with the row of shrubs and the up-front grasses.
The toned paper worked well with an underwash of pastel and alcohol as I started the sky and initial land masses. Here you can see that the dark, foreboding sky worked well with the toned paper and underpainting.
Don't hesitate to experiment with toned paper. You can also tone a white or beige sanded paper with a sepia and orange base as well as darker bases, which can help bring out the brilliance of pastels. Complementary color bases also work well to help your pastel colors "pop."