Stain is a liquid similar to paint that is used to color wood and other absorbent materials. Unlike paints, however, most stains are transparent and penetrate wood rather than forming a film on top. The amount of color can be controlled by wiping off excess stain, or by adding more, before it dries. Stains highlight the grain of wood. If used alone, however, they create a dull finish. For this reason, they usually are coated with a clear substance, such as varnish, which provides a gloss.
Stains contain a solvent, a resin, and pigments or dye. They come in many colors.
