Every pastel company has a full collection of pure, full-strength colors. In addition, each of these colors has a number of lighter or darker shades, made by mixing carefully graded percentages of either white or black chalk to the pure pigment. Or start by choosing a warm and cool version of each of the major colors of the spectrum. Add to these black, white, yellow ochre, burnt sienna, and raw umber. Hard pastels usually come in more limited shades than soft pastels.
Pastels vary in permanence and in hardness.
Some pigments are more permanent than others, and some require more binding agents to adhere into sticks. It is a good idea to choose only those colors identified by true pigment names. Which Surfaces to Choose A pastel painting is very much a marriage of pastel and paper. Smooth surfaces won't hold the pigment. Whether rough or smooth, the paper should be relatively thick, of good quality, and should contain some sizing.