Crayons made from compressed chalk, pigment powder and binders. Paintings made with this crayon are called colored crayon drawings
. The traditional bonding material is astragalus gum. When the bonding material is linseed oil, this crayon is called oil chalk. Colored crayons are used for painting on rough paper, cardboard or specially prepared canvas. Colored crayon drawings are easily damaged, because they are blurred at the touch. Fixatives can protect the picture, but are not desirable because they can darken the color of the picture. The best way to protect pastel crayons is to use glass.
In the case of careful protection, the freshness and preservation time of colored crayons are longer than those of oil painting or watercolor painting. They do not fade like oil paintings, nor do they change tide like watercolors. The beauty of pastel paintings is mainly its soft velvet-like surface, which gives the painting a harmonious depth and atmosphere of color that cannot be achieved by other methods. Colored crayons are particularly suitable for portraits, still lifes, and certain landscape paintings.