Oil pastels are raw pigments combined with oil binders instead of gum. They produce thick, buttery strokes, and their colors are deeper and more luminous, like oil paints. They are also less crumbly and smearing. Oil pastels are suited to direct, spontaneous work, and can be diluted with turpentine or mineral spirits. Choosing your Colors While most paints can be mixed from a relatively limited palette to form many different colors, pastels require a large number of separate sticks to achieve an adequate range of hues and tints.
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.