The Copyright Act gives copyright holders the exclusive right to reproduce works for a limited time period. Fair use is a limitation on this right. Fair use allows people other than the copyright owner to copy part or, in some circumstances, all of a copyrighted work, even where the copyright holder has not given permission or objects.
Section 107 of the U.S. Copyright Act contains a list of the various purposes for which the reproduction of a particular work may be considered fair, such as criticism, comment, news reporting, teaching, scholarship, and research.
Whether a use is fair will depend on the specific facts of the use. Note that attribution has little to do with fair use; unlike plagiarism, copyright infringement (or non-infringement) doesn't depend on whether you give credit to the source from which you copied. Fair use is decided by courts on a case-by-case basis after balancing the four factors listed in section 107 of the Copyright Act. Those factors are:
- The purpose and character of the use of copyrighted work
- Transformative quality - Is the new work the same as the copyrighted work, or have you transformed the original work, using it in a new and different way?
- Commercial or noncommercial - Will you make money from the new work, or is it intended for nonprofit, educational, or personal purposes? Commercial uses can still be fair uses, but courts are more likely to find fair use where the use is for noncommercial purposes.
- The nature of the copyrighted work
A particular use is more likely to be considered fair when the copied work is factual rather than creative.
- The amount and substantiality of the portion used in relation to the copyrighted work as a whole
How much of the copyrighted work did you use in the new work? Copying nearly all of the original work, or copying its "heart," may weigh against fair use. But "how much is too much" depends on the purpose of the second use. Parodies, for example, may need to make extensive use of an original work to get the point across.
- The effect of the use upon the potential market for or value of the copyrighted work
This factor applies even if the original is given away for free. If you use the copied work in a way that substitutes for the original in the market, that will weigh against fair use. Uses of copyrighted material that serve a different audience or purpose are more likely to be considered fair.
These factors are guidelines, and they are not exclusive. As a general matter, courts are often interested in whether or not the individual making use of a work has acted in good faith.
Courts have regarded the following activities as fair use: (Source: 1961 Report of the Register of Copyrights on the General Revision of the U.S. Copyright Law)
- Quotation of excerpts in a review or criticism for purposes of illustration or comment
- Quotation of short passages in a scholarly or technical work, for illustration or clarification of the author's observations
- Use in a parody of some of the content of the work parodied
- Summary of an address or article, with brief quotations, in a news report
- Reproduction by a library of a portion of a work to replace part of a damaged copy
- Reproduction by a teacher or student of a small part of a work to illustrate a lesson
- Reproduction of a work in legislative or judicial proceedings or reports
- Incidental and fortuitous reproduction, in a newsreel or broadcast, of a work located in the scene of an event being reported