What is "fair use" in intellectual property law?
Fair Use is a defense to a claim of copyright infringement. This means that if you were to use a work and you thought your use was "fair use", you would have to be sued for infringement and assert that defense. You or your attorney stating this belief would not prevent you from having to prove this defense in court as part of a copyright infringement claim.
Fair use is a complex concept which requires a balancing of factors as set forth by the Supreme Court (Luther R. Campbell v. Acuff Rose Music Inc., involving the parody of the Roy Orbison song "Pretty Woman" by the band 2 Live Crew). These factors include:
(1) the purpose and character of the use, including whether the use is of commercial or non-profit nature and whether the use is "transformative";
(2) the nature of the copyrighted work (to what extent it merits copyright protection);
(3) the amount and substantiality of the portion used in relation to the work as a whole (how much and how important the part used is when compared to the original work); and
(4) the effect of the use upon the potential market for or value of the original work.
Whether or not something is "fair use" is rarely a clear yes or no question. It requires review of case law and the above factors by an experienced attorney who can assess the level of risk involved in the proposed use.