Pastel is pure pigment, the same pigment used in making all fine art paints. All top quality pastel brands are permanent when applied to conservation ground and properly framed. Pastel that has not been sprayed with fixative contains no liquid binder that may cause other media to darken, yellow, crack or blister with time. Pastels from the 16th century exist today as fresh as the day they were painted.

The pure, powdered pigment, is ground into a paste with a small amount of gum binder then rolled into sticks. The infinite variety of colours in pastel, range from soft and subtle to strong and brilliant. The word pastel, in this case, does not refer to "pale colours" as it is commonly used in cosmetic and fashion venues.

An artwork is created by stroking the sticks of dry pigment across an abrasive ground, embedding the color in the "tooth" of the paper, sandboard, canvas etc. If the ground is completely covered with pastel, the work is considered a pastel painting; a work with much of the ground left exposed is termed a pastel sketch or drawing. Pastel is sometimes combined with watercolour, gouache, acrylic, charcoal or pencil in a mixed-media painting, but it is not compatible with oil paint. Pastel paintings reflect light like a prism. No other medium has the same color power.

Edgar Degas was the most prolific user of pastel and its champion. His protégé, Mary Cassatt, introduced the impressionists and pastel to her friends in Philadelphia and Washington, and thus to the USA.