These Rules of Thumb are an abbreviated summary of the Guidelines terms which provide helpful guidance that we recommend you review. Limit access to students enrolled in the class and administrative staff as needed. Terminate access at the end of the class term . Obtain permission for materials that will be used repeatedly by the same instructor for the same class. So, a use that exceeds the suggestions of the Rules of Thumb may still be fair.
Most people think that the fair use test is difficult.
Actually, it's not so much difficult as it is uncertain - susceptible to multiple interpretations. Two people can review the same facts about a proposed use and come to different conclusions about its fairness. That's because one must make many judgments in the course of weighing and balancing the facts. But that's just what this test is about. The use on the right tends to tip the balance in favor of the copyright owner - in favor of seeking permission.