The term "public domain" refers to creative materials that are not protected by intellectual property laws such as copyright, trademark, or patent laws. The public owns these works, not an individual author or artist. Anyone can use a public domain work without obtaining permission, but no one can ever own it. An important wrinkle to understand about public domain material is that, while each work belongs to the public, collections of public domain works may be protected by copyright.
For example, if someone has collected public domain images in a book or on a website, the collection as a whole may be protectable even though individual images are not. You are free to copy and use individual images but copying and distributing the complete collection may infringe what is known as the “collective works” copyright. Collections of public domain material will be protected if the person who created it has used creativity in the choices and organization of the public domain material. This usually involves some unique selection process, for example, a poetry scholar compiling a book.
Essentially, if a work is within the public domain, there are no ownership rights associated with it and it is not protected by Copyright law.
Orphan Works comprise those materials in which the owner of the copyright cannot be identified or located for the purpose of obtaining permission to use his/her work. Because of the uncertainty over their copyright status, these works are often dropped unless they are clearly in the public domain.
In general, works published after 1977 will not fall into the public domain until 70 years after the death of author, or, for corporate works, anonymous works, or works for hire, 95 years from the date of publication or 120 years from the date of creation, whichever expires first.
Four common ways that works arrive in the public domain: