Fair use provisions determine conditions under which copyrighted material may be used without permission from the copyright holder, and is not an infringement of U.S. law -- which permits copying for purposes of criticism, comment, news reporting, teaching, scholarship, and research.
The United States Code (17 U.S.C. § 107) defines four factors to be weighed when determining if fair use applies:
- The purpose and character of the use, including whether such use is of a commercial nature or is for nonprofit educational purposes;
- The nature of the copyrighted work;
- The amount and substantiality of the portion used in relation to the copyrighted work as a whole; and
- The effect of the use upon the potential market for or value of the copyrighted work.
As the above provisions are rather vague, many legal debates persist over determining fair use. Several publishing associations have enacted guidelines (for example, rules that limit the percentage of a work which may be used for library reserve) that have few correlates to the stated law.
Although fair use is not explicitly defined in U.S. copyright law, it must meet the following criteria:
- The use must not impair the value of the copyright by reducing demand in the marketplace for the original
- The copier must not have used the efforts of the copyright owner as a substitute for his or her own intellectual effort
- The use must be fair by the standards of any reasonable person, not damaging to the original work
 See also
- Fair Use Information from the Stanford University Libraries