There are limitations on the creator’s exclusive rights, most notably fair use.
According to the section 107 of the United States Code, fair use of a copyrighted work for designated purposes such as “criticism, comment, news reports, teaching (including multiple copies for classroom use), scholarship, or research, is not an infringement of copyright” (17 U.S.C. § 107). Four factors are used to determine whether the usage of copyrighted materials is considered fair use. The Copyright Act of 1976 defines these factors as:
1. The purpose and character of the use, including whether such use is of commercial nature or is for nonprofit educational purpose,
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 (17 U.S.C. § 107).
Although fair use may not give creators the opportunity to use copyrighted works as extensively as works in the public domain, fair use provides creators with a chance to build upon or transform copyrighted works.