A work that is derived or adapted from a public domain work can itself be protected by copyright only to the extent that the derived work contains elements of originality contributed by the author of the derived work. For example, an abstract painting of a famous photograph would be protectible, as is the distinctive rendition of the Star Spangled Banner performed by Jimmy Hendrix. The protection available to these works does not remove the underlying work from the public domain, and the author of the derivation has no cause of action against another person who makes a derivation of the same public domain work.

A work that is merely a "slavish copy", or even a restoration of an original public domain work is not subject to copyright protection. In the case of Hearn v. Meyer, 664 F. Supp 832 (S.D.N.Y. 1987), an illustrator attempted unsuccessfully to claim copyright on his painstakingly restored versions of original Wizard of Oz illustrations. The illustrations were in the public domain, and the court found that the act of rendering them with bolder and more vibrant colors was not an original contribution sufficient to remove the restored works from the public domain.