How do I know if something is fair use and not copyright infringement?
Fair use is an affirmative defense to copyright infringement and is a fact-specific inquiry based on 4 factors:
1) The purpose and character of the use, including whether such use is of a commercial nature or is for non-profit 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.
Some common examples of fair use include criticism, comment, news reporting, teaching, scholarship, and research, although each set of circumstances must be analyzed to determine whether the use of copyright-protected works is a fair use.