While it’s true that no strings are attached to using public domain materials, you should be aware of certain potholes on the public domain highway, as described below.
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Multilayered Works
Works such as movies or sound recordings may contain many underlying works, such as musical sound tracks, painted illustrations, or other works. There has been a disturbing trend by some copyright owners to assert protection in an element of a public domain work. For example, the film It’s a Wonderful Life fell into the public domain because of a failure to renew copyright. For years, anyone was free to copy and sell the movie on videotape. However, a production company recently acquired rights to the musical sound track that is used in the movie. That sound track is not in the public domain. The copyright owner of the sound track can now prevent anyone from copying the music, thereby effectively stopping anyone from copying the film (unless the sound track is removed). Multilayered works can create confusion when trying to determine public domain status.
Usually you don’t have to be concerned with this type of legal maneuver as it is only used in connection with popular and older multilayered works such as classic films. It would be difficult, if not impossible, to apply this procedure to a public domain book or painting.
Public Domain Works That Are Modified
Modifications to a public domain work may be protected by copyright and cannot be used without permission. A famous example used in many copyright classes is the artist who paints an elaborate hat and mustache on the Mona Lisa. Even though anyone is free to copy the image of the Mona Lisa, the modified image (with mustache and hat) is protected under the artist’s copyright.
Works Protected by Trademark Law
It is possible that a work may not be protected by copyright, but is still protected by trademark laws. Chapter 10 provides more information on trademarks.
Plagiarism, Attribution, and the Public Domain
If you copy from a public domain writing, do you have to credit the author? The United States Supreme Court has answered, “No,” holding that there is no legal requirement to provide any attribution when public domain works are copied and placed into new works. (Dastar Corp. v. 20th Century Fox Film Corp., 123 S.Ct. 2041 (2003).)
However, just because there is no legal requirement to give credit to the creators of public domain works, doesn’t mean you don’t have to do it. When copying works from the public domain, be careful to avoid plagiarism.
Plagiarism occurs when someone poses as the originator of words he did not write, ideas he did not conceive, or facts he did not discover. Although you cannot be sued for plagiarizing a public domain work, doing so can result in serious professional and personal penalties. For example, in the case of college professors and journalists, it may result in termination; for students, it could lead to expulsion; if done by well-known historians, it can result in public humiliation.
Works Protected in Other Countries
Before 1978, most countries had different periods of copyright protection than the United States. As a result, many works that are public domain in the United States are still protected by copyright in foreign countries and vice versa. Therefore, you may have to research public domain status in each country in which you plan to publish your work.
Compilations
Often an author creates a work by selecting various public domain components and grouping them together. If the selection, coordination, and arrangement of the material is unique, it will be protected as a copyrightable compilation. Example: The owners of the book Bartlett’s Familiar Quotations selected and arranged famous quotes. Anyone may copy a few quotes from Bartlett’s Familiar Quotations, but no one may copy the selection and arrangement of all the quotes.
Works First Published Outside the U.S.
The copyrights of some works first published outside the United States have been resurrected, removing them from the public domain. As a result of international treaties signed in the 1990s, public domain works that meet certain qualifications are now protected. (For a detailed discussion, see The Copyright Handbook, by Stephen Fishman (Nolo).)