Mason Roberts, 38, is part artist and craftsman, part detective and historian. One of a handful of top-level antiques restorers in Kentucky, Roberts examines each damaged piece carefully so that, he says, "you won't be able to tell I did anything" after the restoration.

For example, he uses period pigments and waxes for 18th-century furniture. Shellac — secretions of the female lac bug gathered from the jungles of India — is mixed with denatured alcohol to create finishes authentic to the 1800s and early 1900s. When he needs black shellac, Roberts grinds bits of old phonograph records...