Fair use is an exception to the rights of copyright owners, allowing the public to make limited uses of a protected work for purposes such as education, research, news reporting, criticism, and commentary. Determining whether a use is fair is based on a balancing act of four factors as defined is the Fair Use Statute. All four factors must be considered before a use is deemed fair. The four factors are meant to be flexible and apply to different types of works and uses, thus each case will be unique.
The Fair Use Statute (US Copyright Act, Section 107)
"Notwithstanding the provisions of sections 106 and 106A, the fair use of a copyrighted work, including such use by reproduction in copies or phonorecords or by any other means specified by that section, for purposes such as criticism, comment, news reporting, teaching (including multiple copies for classroom use), scholarship, or research, is not an infringement of copyright. In determining whether the use made of a work in any particular case is a fair use the factors to be considered shall include—
(1) the purpose and character of the use, including whether such use is of a commercial nature or is for nonprofit educational purposes;
(2) the nature of the copyrighted work;
(3) the amount and substantiality of the portion used in relation to the copyrighted work as a whole; and
(4) the effect of the use upon the potential market for or value of the copyrighted work.
The fact that a work is unpublished shall not itself bar a finding of fair use if such finding is made upon consideration of all the above factors."
The first factor examines whether the use "is of a commercial nature or is for nonprofit educational purposes" (US Copyright Act, 17 U.S.C. 107). "Courts look at how the party claiming fair use is using the copyrighted work, and are more likely to find that nonprofit educational and noncommercial uses are fair. This does not mean, however, that all nonprofit education and noncommercial uses are fair and all commercial uses are not fair; instead, courts will balance the purpose and character of the use against the other factors below. Additionally, “transformative” uses are more likely to be considered fair. Transformative uses are those that add something new, with a further purpose or different character, and do not substitute for the original use of the work."
"More Information on Fair Use." Copyright.gov. https://www.copyright.gov/fair-use/more-info.html
"This factor analyzes the degree to which the work that was used relates to copyright’s purpose of encouraging creative expression. Thus, using a more creative or imaginative work (such as a novel, movie, or song) is less likely to support a claim of a fair use than using a factual work (such as a technical article or news item). In addition, use of an unpublished work is less likely to be considered fair."
"More Information on Fair Use." Copyright.gov. https://www.copyright.gov/fair-use/more-info.html
"Under this factor, courts look at both the quantity and quality of the copyrighted material that was used. If the use includes a large portion of the copyrighted work, fair use is less likely to be found; if the use employs only a small amount of copyrighted material, fair use is more likely. That said, some courts have found use of an entire work to be fair under certain circumstances. And in other contexts, using even a small amount of a copyrighted work was determined not to be fair because the selection was an important part—or the “heart”—of the work."
"More Information on Fair Use." Copyright.gov. https://www.copyright.gov/fair-use/more-info.html
"Here, courts review whether, and to what extent, the unlicensed use harms the existing or future market for the copyright owner’s original work. In assessing this factor, courts consider whether the use is hurting the current market for the original work (for example, by displacing sales of the original) and/or whether the use could cause substantial harm if it were to become widespread."
"More Information on Fair Use." Copyright.gov. https://www.copyright.gov/fair-use/more-info.html