Graining is the practice of imitating wood grain on a non-wood surface, or on relatively undesirable wood surface, in order to give it the appearance of a rare or higher quality wood, thereby increase that surface's aesthetic appeal. Graining was common in the 19th century, as people were keen on imitating hard, expensive woods by applying a superficial layer of paint onto soft, inexpensive woods or other hard surfaces. Graining can be accomplished using either rudimentary tools or highly specialized tools. A specialized thick brush used for graining is often called a mottler. Fan brushes, floggers, softening brushes, texture combs and even fingers are used to create various effects. The painting is carried out in layers, with the first layer being a base. Today that is usually done with latex paint in a gold or orange or tan tone, depending on the type of wood the artist is aiming to imitat. A second layer of tempera or thinned paint is applied over the dry base, by means of a sponge or large inexpensive brush. During the 19th century, however, brushes were more commonly used. It can also be applied on bricks and brass, as is more common today.

Graining can also mean the production of any artificial texture on any surface. For example, in printing, making the smooth metal sheets used in modern printing processes coarse. A stoneworking equivalent of graining is marbling.