As a newbie to pastels, I am learning from books and from doing. (I had my first lesson in a studio when I was about 6, but have used media other than pastel, such as watercolor.). Going through Marla Baggetta's "Pastel Step by Step", A Walter Foster Artist's Library Series book, the very first example, the very first step, is "toning a piece of sanded pastel paper with a diluted wash of acrylic paint," yellow ochre in particular. I have never used acrylic but how hard can it be?
Here's my question: what are the advantages and disadvantages of underpainting with acrylic, watercolor, pastel, using colored paper, or skipping underpainting completely?