In many countries, certain uses of copyright-protected works do not infringe the copyright owner’s rights. For example, in the United States, copyright rights are limited by the doctrine of "fair use", under which certain uses of copyrighted material for, but not limited to, criticism, commentary, news reporting, teaching, scholarship or research may be considered fair. U.S. judges determine whether a fair use defence is valid according to four factors, which we’ve listed below for educational purposes. In some other countries, there is a similar concept called "fair dealing" that may be applied differently.
Remember, it is your responsibility to understand the relevant law and whether it protects the use that you have in mind. If you plan to use copyrighted material that you didn’t create, we'd strongly advise you to take legal advice first. Google cannot provide legal advice or make legal determinations.
The four factors of fair use:
1. The purpose and character of the use, including whether such use is of commercial nature or is for non-profit educational purposes
Courts typically focus on whether the use is “transformative”. That is, whether it adds new expression or meaning to the original, or whether it merely copies from the original.
2. The nature of the copyrighted work
Using material from primarily factual works is more likely to be fair than using purely fictional works.
3. The amount and substantiality of the portion used in relation to the copyrighted work as a whole
Borrowing small bits of material from an original work is more likely to be considered fair use than borrowing large portions. However, even a small taking may weigh against fair use in some situations if it constitutes the “heart” of the work.
4. The effect of the use upon the potential market for, or value of, the copyrighted work
Uses that harm the copyright owner's ability to profit from his or her original work by serving as a replacement for demand for that work are less likely to be fair uses.