An oil pastel is a crayon made of pure pigments bound with wax and oil that is available in scholastic, student and professional grades. Oil pastels can be used on a wide variety of surfaces, without the need for priming. They also are more convenient to use than oil paints and can be manipulated to create many of the same effects.
The first oil pastels were developed in the 1920s. They were designed to encourage Japanese children to express themselves with colors and shapes. This type of oil pastel was more deeply colored than a chalk pastel and behaved more like a crayon. Its use in art education became widespread.
In the late 1940s, Pablo Picasso and fellow artist Henri Goetz approached a French art supply manufacturer with their ideas for developing an artist-quality version of the oil pastel. Picasso was intrigued by the possibility that these pastels could be used on many types of surfaces, including unprimed canvas. Goetz wanted a medium that could be directly applied to a painting surface without the use of tools such as brushes or palette knives.
As demand grew for artist-quality oil pastels, a number of other art supply manufacturers began producing their own oil pastels. Artists can now choose oil pastels that are soft and creamy or more like a crayon in consistency. The harder ones can be warmed in the hand to be more pliable when desired. Artist-grade pastels are acid-free and contain pure pigments that are archival quality.
Oil pastels can be used on glass, metal, canvas, art boards and many grades of paper. They are applied directly to the surface in a variety of different techniques. Some artists apply the oil pastels and then use brushes for blending.
Many of the techniques used by oil painters can be transferred to their work with oil pastels. They can layer on color and mix oil pastels with turpentine, mineral oils or other solvents to create glazes. Oil pastels can be used over dried oil painting. They also can be used in mixed-media paintings with watercolors or acrylics.
These pigment crayons are very convenient for using outdoors. An artist needs only to bring his or her oil pastels, drawing surface and any pencils or tools that he or she uses. There is no need for brushes or solvents. The wax and oil binders produce a surface that is never totally dry, enabling the artist to continue working on the picture in his or her studio.
A finished oil pastel piece generally is covered in glass to protect the surface. Oil pastels never dry to the hardness of oils or acrylics. Some people use varnish as an alternative to glass framing.