One of the four factors used to determine whether use of copyrighted material is considered fair use is "the purpose and character of the use." The essence of this factor seems to be "whether and to what extent the new work is 'transformative,' i.e., altering [the original work] with new expression, meaning or message."
I am somewhat confused by the phrase "new expression, meaning or message." Naively (I am a layperson with no legal background), I would consider a TV show featuring Harry Potter characters teaching science to children to have a "new meaning or message". The message of Harry Potter is a story about magic and adventure and good vs evil. The message of my hypothetical TV show is the principles of science. Those are obviously different, so I'm clearly giving new meaning to Harry Potter characters, right?
But it seems that this is not what courts mean by "new expression, meaning or message." For example, Penguin Books once tried to publish a book detailing the OJ Simpson trial using copyrighted elements of The Cat in the Hat. The 9th Circuit Court of Appeals ruled that this was not fair use, and part of their argument was that the book did not satisfy the "new expression, meaning or message" aspect of fair use.
From what I have read, the following things are usually considered fair use (at least with regards to the "purpose and character" factor):
- review for educational purposes
- news reporting
Notably, the Supreme Court has indicated that being a parody doesn't help the fair use argument if "the commentary has no critical bearing on the substance or style of the original composition". In other words, if the borrowed work isn't the target of the parody, then it's not really a parody for fair use purposes.
The common theme I see in these examples of fair use is that the "new expression, meaning or message" is about the original work (commentating on the work, teaching about the work, etc). Is it accurate to say that when courts say "new expression, meaning or message", they are really referring to messages about the original work? Or am I misunderstanding this aspect of fair use?
This is mostly based on what I have read from the opinion for Dr. Seuss Enterprises, L.P. v. Penguin Books USA, Inc.. All the quotes were obtained from this source.