What is Copyright?
Copyright is a federal law that gives creators of media exclusive rights to copy, distribute, and modify the things they create for a limited time.
This is why iTunes charges for songs, and why YouTube videos featuring licensed content if taken down within hours of posting.
What is Fair Use?
Fair use is a doctrine of US Copyright Law, allowing for the limited use of copyrighted material without requiring permission from the copyright holder. It permits legal, non-licensed citation or incorporation of copyrighted material in another creator's work using a 4-part balancing test. The tricky part about Fair Use is that the balancing test is subjective and open to interpretation.
The four factors judges consider are:
If your intended use exceeds copyright restrictions on a particular work and you cannot make a Fair Use Argument, you should seek permission from the copyright owner.
What is this process?