Public domain works are those that are not protected by intellectual property laws, such as copyrights, trademarks, or patents. Anyone can use a public domain work without obtaining permission from the copyright holder.
There are several ways for a work to enter the public domain:
- The copyright expires. In the United States, works published before 1923 are in the public domain.
- The copyright is not renewed. In the United States, copyrights are generally renewed 28 years after they are granted. If the copyright is not renewed, the work enters the public domain.
- The copyright holder explicitly donates the work to the public domain.
- The copyright holder fails to follow required formalities. For example, in the United States, works published before 1978 without a copyright notice are in the public domain.
Note that simply not protecting a work with copyrights, trademarks, or patents does not mean the work is in the public domain. The creator of the work must take action to place the work in the public domain.
There are many works of art in the public domain, such as the Mona Lisa and The Great Wave off Kanagawa. Public domain works are a key part of the cultural heritage of humanity. They can be used freely for any purpose, without obtaining permission from the copyright holder.
