The word pastel is derived from pastello, Italian for paste.
Chalk Pastels are made from finely ground pigment mixed with water and a small amount of glue, usually gum tragacanth. Pure colors are made lighter by adding white chalk called calcium carbonate. The finished paste is shaped into round or square sticks and allowed to harden. The softness or hardness of a pastel depends on the nature of the pigment and on how much binder is used, the more glue the harder the stick.
Oil pastels are made by cooking raw pigments with an oil-soluble wax binder into a buttery paste, which is then moulded into crayons.
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