Hi Diana,
The pieces for this blog were all done on sanded paper. The top one was on Wallis Belgium mist--a midtone grey, which I let show through with no underpainting. The three middle ones were done on Pastel Premier in either clay or rust, with no underpainting--I used the tone of the paper to unify and show through. The bottom one was done on Uart paper 400 grit with an underpainting.