What is 'Public Domain?'*
The public domain refers to works (i) no longer protected by copyright (that is, where the copyright has expired), and (ii) belonging to categories of works not protected by copyright law.
In addition, in some countries (including the United States and, for certain purposes, the United Kingdom) government works are defined by law as being in the public domain (not protected by copyright) from the moment of their creation.
Thus, differences in how national copyright laws define the duration of copyright and list the categories of works protected, result in different definitions of the public domain on a country-by-country basis.
In Europe, the Europeana Connect project has developed a helpful Public Domain Calculation tool.
Public Domain in the United States
The legal concept of the public domain as it applies to copyright law should not be confused with the fact that a work may be publicly available, such as information found in books or periodicals, or on the Internet. The public domain comprises all those works that are either no longer protected by copyright or never were.
Essentially, all works first published in the United States prior to 1923 are considered to be in the public domain in the United States, as are works published between 1923 and 1963 on which copyright registrations were not renewed. Materials created since 1989, other than those created by the U.S. federal government, are presumptively protected by copyright. Therefore, the likelihood that materials of greatest interest are in the public domain is low. In addition, you must also consider other forms of legal protection, such as trademark or patent protection, before reusing third-party content.
Public domain materials generally fall into one of four categories:
Also, in rare instances, works may be “dedicated” (donated) to the public domain.