Purpose & character is one of the factors to determine Fair Use. Fair Use is in favor of: teaching, personal, reseach and transformative. According to the U.S. Copyright office the purpose will be weighed against the other factors of: nature of the copyrighted work, amount and substantiality of the portion, and effect & value of copyright work. As for transformative use they add something new and doesn’t substuite the orginal work.
Example of fair use by summaries of fair use cases from Standord Library:
TCA Television Corp. v. McCollum: Puppet Person mocks pretending to be author.
Case was seen transformative based on needing to know the orginal play to get the joke.
Religious Technology Center v. Pagliarina: Quotation from Church of Scientology posts on internet.
Purpose for fair use was commentary.
Some questions to consider for purpose and character include:
Is this work offer something better?
Is this new work considered a copy?