Works are in the public domain if they are not covered by intellectual property rights, such as copyright, at all, or if the intellectual property rights to the works has expired.
Congress has restored expired copyrights several times: "After World War I and after World War II, there were special amendments to the Copyright Act to permit for a limited time and under certain conditions the recapture of works that might have fallen into the public domain, principally by aliens of countries with which we had been at war." Works published with notice of copyright or registered in unpublished form in the years 1964 through 1977 automatically had their copyrights renewed for a second term. Works published with notice of copyright or registered in unpublished form on or after January 1, 1923, and prior to January 1, 1964, had to be renewed during the 28th year of their first term of copyright to maintain copyright for a full 95-year term. With the exception of maps, music, and movies, the vast majority of works published in the United States before 1964 were never renewed for a second copyright term.
Works "prepared by an officer or employee of the U.S. government as part of that person's official duties" are automatically in the public domain by law. Examples include military journalism, federal court opinions (but not necessarily state court opinions), congressional committee reports, and census data. However, works created by a contractor for the government are still subject to copyright. Even public domain documents may have their availability limited by laws limiting the spread of classified information.
The claim that "pre-1923 works are in the public domain" is correct only for published works; unpublished works are under federal copyright for at least the life of the author plus 70 years. For a work for hire, the copyright in a work created before 1978, but not theretofore in the public domain or registered for copyright, subsists from January 1, 1978, and endures for a term of 95 years from the year of its first publication, or a term of 120 years from the year of its creation, whichever expires first. If the work was created before 1978 but first published 1978?2002, the federal copyright will not expire before 2047.
Until the Berne Convention Implementation Act of 1988, the lack of a proper copyright notice would place an otherwise copyrightable work into the public domain, although for works published between January 1, 1978, and February 28, 1989, this could be prevented by registering the work with the Library of Congress within five years of publication. After March 1, 1989, an author's copyright in a work begins when it is fixed in a tangible form; neither publication nor registration is required, and a lack of a copyright notice does not place the work into the public domain.
Under the Copyright Term Extension Act old works will resume entering the Public Domain in 2019.
Very few sound recordings are in the public domain in the United States. Sound recordings fixed in a tangible form before February 15, 1972, have been generally covered by common law or in some cases by anti-piracy statutes enacted in certain states, not by federal copyright law, and the anti-piracy statutes typically have no duration limit. The 1971 Sound Recordings Act, effective 1972, and the 1976 Copyright Act, effective 1978, provide federal copyright for unpublished and published sound recordings fixed on or after February 15, 1972. Recordings fixed before February 15, 1972, are still covered, to varying degrees, by common law or state statutes. Any rights or remedies under state law for sound recordings fixed before February 15, 1972, are not annulled or limited by the 1976 Copyright Act until February 15, 2067. On that date, all sound recordings fixed before February 15, 1972, will go into the public domain in the United States.
For sound recordings fixed on or after February 15, 1972, the earliest year that any will go out of copyright and into the public domain in the U.S. will be 2043, and not in any substantial number until 2048. Sound recordings fixed and published on or after February 15, 1972, and before 1978, which did not carry a proper copyright notice on the recording or its cover entered the public domain on publication. From 1978 to March 1, 1989, the owners of the copyrights had up to five years to remedy this omission without losing the copyright. Since March 1, 1989, no copyright notice has been required.
In the United States, the images of Frank Capra's film It's a Wonderful Life (1946) entered into the public domain in 1974, because the copyright holder failed to file a renewal application with the Copyright Office during the 28th year after the film's release or publication. However, in 1993, Republic Pictures utilized the 1990 United States Supreme Court ruling in Stewart v. Abend to enforce its claim of copyright because the film was a derivative work of a short story that was under a separate, existing copyright, to which Republic owned the film adaptation rights, effectively regaining control of the work in its complete form. Currently, Paramount Pictures owns the copyright to the film.
Charles Chaplin re-edited and scored his 1925 film The Gold Rush for reissue in 1942. Subsequently, the 1925 version fell into the public domain when Chaplin's company failed to renew its copyright in 1953, although the 1942 version is still under US copyright.
The distributor of the cult film Night of the Living Dead, after changing the film's title at the last moment before release in 1968, failed to include a proper copyright notice in the new titles, thereby immediately putting the film into the public domain after its release. This provision of US copyright law was revised with the United States Copyright Act of 1976, which allowed such negligence to be remedied within five years of publication.
A number of TV series in America have lapsed into the public domain, in whole or only in the case of certain episodes, giving rise to wide distribution of some shows on DVD. Series that have only certain episodes in the public domain include Petticoat Junction, The Beverly Hillbillies, The Dick Van Dyke Show, The Andy Griffith Show, The Lucy Show, Bonanza, Annie Oakley, and Decoy.
Laws may make some types of works and inventions ineligible for monopoly; such works immediately enter the public domain upon publication. Many kinds of mental creations, such as publicized baseball statistics, are never covered by copyright. However, any special layout of baseball statistics, or the like, would be covered by copyright law. For example, while a phone book is not covered by copyright law, any special method of laying out the information would be.
In the past, a work would enter the public domain in the United States if it was released without a copyright notice. This was true prior to March 1, 1989, but is no longer the case. Any work (of certain, enumerated types) now receives copyright as soon as it is fixed in a tangible medium.
There are several references to putting copyrighted work into the public domain. The first reference is actually in a statute passed by Congress, in the Computer Software Rental Amendments Act of 1990 (Public Law 101?650, 104 Stat. 5089 (1990)). Although most of the Act was codified into Title 17 of the United States Code, there is a very interesting provision relating to "public domain shareware" which was not, and is therefore often overlooked.
One purpose of this legislation appears to be to allow "public domain shareware" to be filed at the Library of Congress, presumably so that the shareware would be more widely disseminated. Therefore, one way to release computer software into the public domain might be to make the filing and pay the $20 fee. This could have the effect of "certifying" that the author intended to release the software into the public domain. It does not seem that registration is necessary to release the software into the public domain, because the law does not state that public domain status is conferred by registration. Judicial rulings supports this conclusion, see below.
By comparing paragraph (a) and (c), one can see that Congress distinguishes "public domain" shareware as a special kind of shareware. Because this law was passed after the Berne Convention Implementation Act of 1988, Congress was well aware that newly created computer programs (two years worth, since the Berne Act was passed) would automatically have copyright attached. Therefore, one reasonable inference is that Congress intended that authors of shareware would have the power to release their programs into the public domain. This interpretation is followed by the Copyright Office in 37 C.F.R. § 201.26.
The Berne Convention Implementation Act of 1988 states in section twelve that the Act "does not provide copyright protection for any work that is in the public domain." The congressional committee report explains that this means simply that the Act does not apply retroactively.
Although the only part of the act that does mention "public domain" does not speak to whether authors have the right to dedicate their work to the public domain, the remainder of the committee report does not say that they intended copyright to be an indestructible form of property. Rather the language speaks about getting rid of copyright formalities in order to comply with Berne (non-compliance had become a severe impediment in trade negotiations) and making registration and marking optional, but encouraged. A fair reading is that the Berne Act did not intend to take away author's right to dedicate works to the public domain, which they had (by default) under the 1976 Act.
Although there is support in the statutes for allowing work to be dedicated to the public domain, there cannot be an unlimited right to dedicate work to the public domain because of a quirk of U.S. copyright law which grants the author of a work the right to cancel "the exclusive or nonexclusive grant of a transfer or license of copyright or of any right under a copyright" thirty-five years later, unless the work was originally a work for hire.
It is unsettled how this section would mesh with a purported public domain dedication. Several interpretations are possible:
Another form of support comes from the seminal case Computer Associates Int'l v. Altai, 982 F.2d 693. This case set the standard for determining copyright infringement of computer software and is still followed today. Moreover, it was decided by the Second Circuit appellate court, which is famous for handing down some of the most well-reasoned American copyright decisions. In this case, it discusses the public domain.
This decision holds that computer software may enter the public domain through "freely accessible program exchanges and the like," or by becoming "commonplace in the computer industry." Relying only on this decision, it is unclear whether an author can dedicate his work to the public domain simply by labeling it as such, or whether dedication to the public domain requires widespread dissemination.
This could make a distinction in a CyberPatrol-like case, where a software program is released, leading to litigation, and as part of a settlement the author assigns his copyright. If the author has the power to release his work into the public domain, there would be no way for the new owner to stop the circulation of the program. A court may look on an attempt to abuse the public domain in this way with disfavor, particularly if the program has not been widely disseminated. Either way, a fair reading is that an author may choose to release a computer program to the public domain if he can arrange for it to become popular and widely disseminated.