The public domain consists of works that are free of copyright. This means you don’t need permission to use, alter or share these works. For instance, many classic artworks and literature are in the public domain.
Expired copyright: life +70 years
In the European Union copyright expires 70 years after the death of the maker.
If a company holds the copyright or the creator is anonymous 70 years after first publication.
It's also possible a work was never entitled to copyright to begin with. For more information on this, read the segment on Copyright Basics in this wiki.
How do you recognize a Public Domain work
It can be difficult to recognize if a work is in the public domain. There are two labels that can be used to make a public domain work recognizable as such:
Although public domain works are free of copyright, you should take note of the following:
Moral rights may still exist
This means that if distortion, misrepresentation or interference of the work negatively affects the makers honour, the maker or their descendants could protest.
A work may be in the public domain in one country, but not in another
Different countries have different terms for copyright expiration. Follow the rules of the country where you (re)use the work. E.g. in Mexico copyright expires 100 years after the death of the maker, in Yemen this is only 30 years. Some countries may have extentions or other rules in their copyright law that make it less clear cut if something it in the Public Domain. For instance, The diary of Anne Frank is in not yet in the public domain in the Netherlands. You can read more about this in: Public Domain: why it is not that simple in Europe, by Katarzyna Strycharz.
Other intellectual property restrictions may apply
E.g. a logo of the publisher on the cover of a public domain book may be protected by trademark law.
Take note of privacy or culturally or morally sensitive issues
E.g. works that are cultural heritage of Indigenous communities. Check out Mukurtu, and the Traditional Knowledge Labels to learn more about this.
Derivatives of public domain works may be copyrighted
If someone used a public domain work to turn it into a new work, this creator will have copyright on the parts of the new work that are new and original.
Where do you find public domain works
Not all public domain works will be marked with a CC0 license or a Public Domain mark. There are however websites that offer mainly public domain sources. For example Project Gutenberg, Public Domain Review, Europeana, Flickr’s the Commons, the Smithsonian and the Rijksmuseum. Check out the next segment for more handy sources.