If a work is in the public domain, that means there are no intellectual property laws protecting it. Anyone can use it. This is why you will sometimes see modern novels using a cast of characters from a famous novel of the past, for example. That novel has entered the public domain and so the creative work is owned by everyone and exclusive to no one.
Why would this happen? The four most common ways are:
- The work was originally copyrighted, but that expired.
- The person who owned the copyright meant to renew it but failed to do so properly.
- The work was put into the public domain intentionally by the copyright owner, who no longer wanted the protection.
- It is a type of work that can’t be copyrighted under current laws anyway.
In the example above, using novels, what often happens is that the author has passed away. Eventually, the copyright will expire if it is not purchased by that person’s estate or some other entity.
It may just be part of a work that’s in the public domain
One of the important things to remember is that a work could be partially copyrighted and partially in the public domain.
An example of this is if someone writes a book and includes photographs. They didn’t take the photographs, but they use images from the public domain. Anyone else could theoretically use those same images, but the text within the book would still be copyrighted, and cannot be used elsewhere without permission.
There are situations in which copyright laws get confusing or there are disputes about how certain information can be used. Those involved need to be sure that they understand all of their legal options.