If a work is still protected by copyright and not yet in the public domain, is it completely locked down, unable to be used by anyone but the copyright owner? No, U.S. copyright law places some limitations on copyright owners’ exclusive rights. In particular, the fair use provision of U.S. copyright law allows anyone to make limited use of copyrighted works in certain circumstances, without payment or permission.

The law doesn’t specify exactly what uses are and aren’t fair use, but it lists types of activities that may qualify as fair use and also lays out the framework for determining whether a specific use is indeed a fair use:

• Uses That May Qualify as Fair Use: According to the fair use clause, using a copyrighted work “for purposes such as criticism, comment, news reporting, teaching (including multiple copies for classroom use), scholarship, or research” may qualify as fair use and therefore not be a copyright infringement, depending on the specifics of the situation (see below).
   
• Framework for Determining Fair Use: According to the fair use clause, the following four factors must be considered when determining whether a specific use is a fair use:
  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.
      

Formulas, Rules, Guidance?

There are no exact formulas or bright-line tests for determining fair use. In fair use court cases, each use is assessed individually based on its specific circumstances.

However, there are guides and tools to help. For example, the open access book Fair Use for Nonfiction Authors: Common Scenarios with Guidance from the Authors Alliance is extremely informative, as are the Fair Use Checklist from Columbia University Libraries and the codes of best practices in fair use from the Center for Media & Social Impact.