Measuring Fair Use: The Four Factors
Unfortunately, the only way to get a definitive answer on whether a particular use is a fair use is to have it resolved in federal court. Judges use four factors in resolving fair use disputes, which are discussed in detail below. It's important to understand that
these factors are only guidelines and the courts are free to adapt them to particular situations on a case-by-case basis. In other words,
a judge has a great deal of freedom when making a fair use determination and the outcome in any given case can be hard to predict.
The four factors judges consider are:
1. the purpose and character of your use
2. the nature of the copyrighted work
3. the amount and substantiality of the portion taken, and
4. the effect of the use upon the potential market.
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