The Fair Use rule of copyright law is intended to support teaching, research, and scholarship. It allows individuals to make limited use of a copyrighted work for purposes such as criticism, commentary, or teaching, without obtaining permission from the copyright holder.
There are four factors to consider in order to determine whether or not a particular use would be considered Fair Use:
1. What is the purpose of the use?
Fair use favors uses that are nonprofit, educational, or personal, for purposes of teaching, research, criticism, scholarship, commentary, or news reporting. Fair use does not apply to uses that are commercial, for-profit, or entertainment.
2. What is the nature of the work?
Fair use is more likely to apply to published works over unpublished works, and factual works over creative works such as art, music, plays, and novels.
3. How much of the work will you use?
Fair use favors using small amounts of a work, rather than large parts of a work or the whole work in entirety. If the small part of the work constitutes a large part of the whole, the use may weigh against fair use, even if the actual amount being used is small.
4. What effect will the use have on the market for the work?
Fair use does not favor uses that would deprive the copyright owner of income or a potential market for their work.
Four Factors of Fair Use, presented by Julie Ahrens, Stanford Center for Internet & Society.