Endorsed by the Oil Pastel Association of America (OPA), Holbein Artists’ Oil Pastels come in a superb range of colors that feel and move like a chalk pastel. These pastels are the culmination of more than 50 years of research, development, and manufacturing expertise in the oil pastel field. The manufacturing process is entirely automated to ensure uniformity of color distribution. They handle evenly and cleanly without stickiness and, once down, provide excellent surface stability. Because of the wax content and highly refined mineral oil used in their manufacture, they will never harden completely. It is recommended that the surface not be fixed, as this will detract from the vibrancy of the pigments. They can be applied to almost any ground, and used over acrylic and oil color. Unlike oil pastels that use vegetable oils, Holbein Artist Oil Pastels are inert once down and will not dry out or crack. Finished works of art are usually mounted under glass. Each oil pastel measures 3/8" square × 2-3/4" long. Holbein Artists’ Oil Pastels are manufactured to the Munsell color standard for hue, value, and chroma. Note — Please refer to the item specs tab for set information.