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Copyright 2004-2019, Peter B. Hirtle. Use of this chart is governed by the Creative Commons Attribution 3.0 License.


Footnote 1:

  1. This chart was first published in Peter B. Hirtle, "Recent Changes To The Copyright Law: Copyright Term Extension," Archival Outlook, January/February 1999. This version is current as of 1 January 2019. The most recent version is found at For some explanation on how to use the chart and complications hidden in it, see Peter B. Hirtle, "When is 1923 Going to Arrive and Other Complications of the U.S. Public Domain," Searcher (Sept 2012). The chart is based in part on Laura N. Gasaway's chart, "When Works Pass Into the Public Domain," at <>, and similar charts found in Marie C. Malaro, A Legal Primer On Managing Museum Collections (Washington, D.C.: Smithsonian Institution Press, 1998): 155-156. A useful copyright duration chart by Mary Minow, organized by year, is found at . A "flow chart" for copyright duration is found at , and a “tree-view” chart on copyright is at . Several U.S. copyright duration calculators are available online, including the Public Domain Sherpa ( and the Durationator (in beta at Europeana’s public domain calculators for 30 different countries outside of the U.S. (at The Open Knowledge Foundation has been encouraging the development of public domain calculators for many countries: see See also Library of Congress Copyright Office. Circular 15a, Duration of Copyright: Provisions of the Law Dealing with the Length of Copyright Protection ( Washington, D.C. : Library of Congress, 2004) Further information on copyright duration is found in Chapter 3, "Duration and Ownership of Copyright," in Copyright and Cultural Institutions: Guidelines for Digitization for U.S. Libraries, Archives, and Museums, by Peter B. Hirtle, Emily Hudson, and Andrew T. Kenyon (Ithaca, NY: Cornell University Library, 2009) available for purchase at and as a free download at Additional guidance on the public domain may be found in Melissa Levine, Richard C. Adler,and Justin Bonfiglio. Finding the Public Domain: Copyright Review Management System Toolkit (Ann Arbor, Michigan: Michigan Publishing, 13 June 2016) and Menesha A. Mannapperuma, Brianna L. Schofield, and Andrea K. Yankovsky, et. al. Is it in the Public Domain? (Berkeley, CA: Samuelson Law, Technology & Public Policy Clinic at the University of California, Berkeley, School of Law, 27 May 2014)