How can something fall into public domain?

Answer 1

There are generally three ways:

• the material is not copyrightable under the statutes,
• the owner failed to properly claim or renew the copyright, or
• the copyright claim has expired.

In recent years, however, some authors or copyright owners have deemed their works "public domain" simply by permanently disclaiming any right to enforce the copyright. Since the legal copyright is still in force until it expires, this is not "the same" as public domain.

Answer 2

Works can arrive in the public domain in a number of ways:

1) Copyright can expire at the end of its natural term

2) Copyright failed the necessary formalities (notice) or was not renewed

3) Copyright was abrogated (voluntarily placed in the public domain by the author). Note that this does NOT mean there "is no copyright" -- merely that it can no longer be effectively enforced.

4) The work is the output of a government entity (In the US works by employees or officers of the US government are automatically public domain). However, it is certainly possible for the government to hire contractors to do copyrighted works and to transfer the copyright ownership to the government.

There are also entire classes of works that are public domain because copyright does not apply to such works. For example, under US law, "In no case does copyright protection for an original work of authorship extend to any idea, procedure, process, system, method of operation, concept, principle, or discovery, regardless of the form in which it is described, explained, illustrated, or embodied in such work." 17 USC § 102(b). For example, a piece of literature (software) that is the only possible way to describe a computer function is not copyrightable.

Answer 3

Works can fall into the public domain...

1) when copyrights reach the end of term and expire
2) when a work is donated to the public domain by the author.
3) if legislation is amended.