As their name suggest, these pastels have oil and wax binders (some are water-soluble). Pigments and varying opaque additives are incorporated into their composition in differing proportions.
This means that there is a wide range of pastels from hard to soft, to colours more or less intense, transparent or opaque.
They come in stick form and in its simplest version they are often children’s first crayons.
The end result is that of a large coloured pencil: the shades can be mixed, layered or blended with the finger using a solvent (turpentine or water).
By its nature, the pastel clings to almost all surfaces but its application is helped by a little grain.
Normally used on paper but some artists use it with canvas often resulting in the work resembling an oil painting.