Wood graining is the art of making surfaces look like wood. This sometimes means graining cheaper, more common woods to look like rarer woods or, as in the photo on the below, to make metal look like wood.

Tools for graining are varied. Some examples are combs, feathers, rags, leather, check rollers, and special brushes such as blenders, liners, and floggers. Better blenders and floggers are usually made from Badger hair.
Graining, skillfully executed can turn white pine into rarer species from mahogany, ebony or birdseye maple.

Wood grained metal frames.  Old Atlanta City Hall        More wood graining.