Oil Pastels are lovely to work with. They blend and layer beautifully.
Because of the oil in the mix, they don’t produce clouds of chalky powder. They are easily combined with other media and, by layering, you can even get an impasto depth impossible with regular pastels.
You can think of oil pastels as a cross between chalk pastels and wax crayons. They are made by combining pigment powder with a non-drying oil and wax binder.
Oil pastels are a relatively modern art media, developed by two Japanese artists after the end of World War I.
Their goal was to break the mold of formulaic art training then extant in Japan.
Students spent countless hours copying intricate ideograms with black India ink. No color; no room for self-expression.
Kanae Yamamoto and his brother-in-law, Shuku Sasaki, founded the Sakura Cray-Pas Company in 1921. By 1924, they had developed the first satisfactory oil pastels.
Oil pastels were an immediate commercial success and many other companies took up production, adding refinements and variations of their own.
In 2004, the Oil Pastel Society was founded "to promote the knowledge and understanding of oil pastel as a fine art medium and to expand the awareness of oil pastel to other artists, galleries, the media, and the general public".
You’ll find some lovely examples of oil pastel art on their
Gallery Pages.
eHow.com has a complete series of How-To Oil Pastel Videos that illustrate a variety of oil pastel techniques and looks.
The video below shows well-known new Mexico wildlife and landscape artist, Gary Garrett, doing a landscape with oil pastels. I love how it illustrates the layering and blending capabilities of the medium.