It can be difficult and time-consuming to determine the copyright status of a work, given that copyright laws have changed over time. Works on which the copyright term has expired and works which were never covered by copyright (such as US government documents) are said to be in the public domain.
If you’d like to know whether a particular work is in the public domain, it will be helpful to know, for starters:
- whether it was published, and if so, when;
- for unpublished works and works made after 1977, who was the author, have they died, and if so, when; and
- in what country was the work first published?
Once you have that information handy, two excellent resources to assess whether a work has passed into the public domain are:
- Copyright Term and the Public Domain in the United States , a comprehensive chart maintained by the Copyright Information Center at the Cornell University Library.
- Copyright Research (Stanford), a chapter from the legal publisher NOLO.
A key variable that will rear its head for works first published before 1964 is the question whether a work had its copyright renewed after it’s initial 28-year term. Many works were not renewed and rose into the public domain decades ago, but a thorough search of the renewal records is required to determine if this is the case for any particular work. To learn more, see John Mark Ockerbloom’s excellent guide to researching renewal.
Some other useful resources:
- Copyright Status Databases collects the key online resources you can search for particular works by name to determine whether and when they were registered, renewed, or otherwise may have risen into the public domain.
- How to Investigate the Copyright Status of a Work, US Copyright Office Circular
- Is It in the Public Domain? (full guide) (UC Berkeley Samuelson Law, Technology, and Public Policy Clinic)
- Is It in the Public Domain? (flow charts) (UC Berkeley Samuelson Law, Technology, and Public Policy Clinic)
- ALA, the Digital Copyright Slider
- VRA, the Digital Image Rights Computator
The web contains a panoply of additional information on the public domain, as do any number of books. Be careful as you explore, however. Most importantly, watch out for resources that treat 1923 as a significant year—starting in 2019, that year is no longer significant. Works from 1923 entered the public domain in 2019, those from 1924 went PD in 2020, and so 0n. “Published more than 95 years ago” has replaced “published prior to 1923” as the useful rule of thumb for judging whether an older work is in the public domain.