Oil pastels were first developed in Japan in 1921. This cross between a wax crayon and a pastel chalk was originally produced by the Sakura Crayon Company. They were first used by schools in Japan to instruct students in Western-style art. They have been sold under the name Cray-Pas since 1927 and have been used to teach generations of school children all around the world to draw and paint.
In 1947 two artists, Pablo Picasso and Henri Goetz, asked paint and pastel manufacturer Henri Sennelier to design a professional version of Cray-Pas. Two years later, with the help of Goetz and Picasso, Sennelier produced the first professional oil pastels, which are still are known for their brilliant color palette and creamy consistency.
Following Picasso's lead, many artists began experimenting with the medium, and galleries began to show and sell oil pastel works. By the 1980s, more and more serious artists were using oil pastels, prompting other paint makers to introduce their own product lines. Now, in addition to Sennelier, oil pastels are produced by Caran d'Ache, Holbein, Talens and Grumbacher, as well as numerous small companies.
According to oil pastel expert Kenneth Leslie, Picasso told Sennelier, "I want a colored pastel that I can paint on anything, wood, paper, canvas, metal, etc. without having to prepare or prime the canvas." Because oil pastels use wax and inert oils as the binder, they have excellent adhesive properties and will stick to a wide variety of surfaces. They are also completely acid free and, because they never harden, they never crack or peel. This ability to be used on different types of supports explains part of the appeal for contemporary artists.
Oil pastels can be worked in a great variety of techniques. They can be used lightly on a rough paper or fabric, and the result is similar to pastel chalks, without the dust. They can also be applied in heavy layers on a rigid support, creating a sort of impasto technique. Oil pastels can be manipulated with brushes dipped in either solvents or oils, on both canvas and panels. They can be layered and scratched away in a type of sgraffito. The range of techniques and supports that can be used, with very few technical constraints, give artists great freedom of expression along with archival stability.
Oil pastels are a "fast" medium, simple to work with, and easy to carry, for painting on location. They come in a brilliant array of colors and blend easily. They can be used to sketch on location and then, back in the studio, the same materials can be used to complete a permanent work of art. This was, in fact, what Henri Goetz was after when he started working in oil pastels. Unlike traditional oil paintings, artwork created with oil pastels does not need time to dry before transporting or framing.