Orphan works

An orphan work is a copyrighted work for which the copyright owner cannot be contacted.

When the name of the creator or copyright owner of an orphan work may be known but other than the name is unknown. The work is not orphaned when the copyright owner protects her identity but provides means to contact her. Reasons for a work to be orphan include that the copyright owner is unaware of her ownership or that the copyright owner has died or gone out of business, in case of companies, and it is not possible to establish to whom ownership of the copyright has passed.

The most of orphan works exist in the collections of libraries, archives and museums, but precise figures are not readily available. Examples of orphan works include photographs which do not note the photographer, such as photos from scientific expeditions and historical images, old folk music recordings, little known novels and other literature.

Orphan works are not available for use by filmmakers, archivists, writers, musicians, and broadcasters. Because the copyright owner can not be identified and located historical and cultural records such as period film footage, photographs, and sound recordings can not be incorporated in contemporary works. mostly because of fear that a re-appearing copyright owner may sue them for damages.

The increase in orphan works is the result of two factors: that copyright terms have been lengthened, and that copyright is automatically conferred without registration or renewal.

Source - Wikipedia