When you take a photograph, write a poem, or even jot down a to-do list, your work is automatically protected under U.S. Copyright Law, and people will usually need to ask your permission to share your creation online, translate it into new languages, or perform it in front of an audience. Eventually, the copyright will expire, as it already has for millions of works of art, music, film, and literature. These materials have become part of the "public domain," collections that are legally available for anyone to reuse or remix.
An item might be in the public domain in the U.S. if:
Anyone who owns a copyright may also share their work as part of the public domain, meaning others may legally use it without permission. Usually this is done by labeling with a "CC0" license; this and some other licenses allow for almost any use, commercial or noncommercial.
It's important to remember that just because it is legal to use something, this doesn't always make it right. There's a complex history behind every cultural work, and even if the copyright has expired sharing the material could invade someone's privacy or appropriate aspects of someone else's culture. Many works in the public domain were created in the 19th or early 20th centuries and contain racist imagery that continues to be harmful and potentially traumatic today.
This guide page was created using information from the Copyright Law Basics guide page from the George A. Smathers Libraries at the University of Florida; the original work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.