Polychromos artists’ pastels contain a high level of pigment, and are free of lubricants and wax. The crayons can be smudged to create fine transitions of colour. Harder than the soft pastel crayons, Polychromos crayons are also well suited to drawing. The square cross-section assists in the drawing of very fine details, as well as the shading of larger areas. Polychromos artists' pastels are characterised by their stable consistency, economy of use and excellent adherence to paper, cardboard, wood and stone. Only minimal fixing is required, ensuring that the pastel drawings retain their vividness of colour. Polychromos artists' pastel crayons can be ground into a fine pigment powder using sandpaper, and then mixed with oil, resin or an acrylic medium to form paint.