Copyright Law describes a collection of exclusive rights for creators (authors, artists, inventors, etc.) of original works. U.S. copyright law is referred to in the Constitution, where Congress is given the power "to promote progress of science and useful arts, by securing for limited times to authors and inventors the exclusive right to their respective writings and discoveries," (Article I, Section 8, Clause 8).
Though it has been revised and updated several times, most recently in the U.S. Copyright Act of 1976, the core rights given to creators have essentially remained the same:
Works in the public domain are not protected by copyright, either because the length of copyright has run out or the copyright owner has placed the work in the public domain and made it available for use by anyone without restriction. Every country has different rules about the public domain. As of 2019, any work created in the U.S. in or before 1924 is in the public domain.
Each year from 2019 on, more works will be released into the public domain on New Year's Day, based on the year they were created.
For more information about the public domain, see:
Remember, if you use a work in the public domain, you still need to cite its source!
One of the rights reserved for creators is the right to distribute copies to the public by sale or other transfer of ownership, including licensing. Creative Commons licenses allow the creator to reserve some rights, while encouraging participation in the cultural dialog by applying a minimal license that allows copying and redistribution of their work. There are 4 restrictions that a Creative Commons license can require:
The Creative Commons website explains the licenses and what they allow. A creator can also apply a CC0 or Public Domain Mark provided by Creative Commons to signal that they are not reserving any rights to their work, or that there are no known restrictions to the reuse of the work.
Locating and using openly licensed, creative commons, or public domain content is a great alternative to requesting permissions or doing a fair use analysis on copyrighted images or other educational content. The following sites are a good starting point for your search:
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