As an intellectual property lawyer who works with comic book creators and who hosts panels at comic book conventions, I answer a lot of questions about copyright law. As of August 2017, here are five of the most frequently asked questions.
1) If I place a copy of my work in an envelope and mail it to myself, does this give me copyright protection?
This is what’s known as a poor man’s copyright. It’s not a real thing. Once you have created your work, you own the copyright. Registering your work with the Copyright Office solidifies your claim of ownership and grants you some additional rights regarding enforcement.
2) How do I prevent someone from stealing my idea?
The answer to this question varies. The simplest way is to not tell anyone about your fantastic idea. The second best solution is to have everyone you tell about your idea sign a non-disclosure agreement, which can be burdensome and impractical. Typically, the best approach is to write down as much of your idea as possible in a detailed synopsis, outline, etc. This shows you have taken steps to actually turn your idea into a copyrightable work. If you do need to discuss your idea with someone else, either give them the synopsis you’ve prepared or, if you’re having a conversation and there is not an opportunity to get a signed agreement, don’t be as thorough in your descriptions. Additionally, it’s always a good idea to document who knows about your project.
3) Other people are making and selling fan art pieces, so it’s legal, right?
No. Just because others are violating someone’s copyright rights and not being stopped does not give you a free license to do the same. A copyright owner could come along at any time and enforce its rights through cease-and-desist letters, DMCA takedown notices, or lawsuits. If you are making and selling art using the intellectual property of others without their permission, you are likely infringing on their rights. Be careful. For more, check out my previous posts on fan art: Is Fan Art Legal? and Fan Art and Fair Use - An Update.
4) If my work is 10/20/30% different than the original work I’ll be fine, right?
There is no set percentage that would make your work non-infringing. One of the factors courts look at is whether the new work is “transformative.” The Copyright Office describes transformative works as “those that add something new, with a further purpose or different character, and do not substitute for the original use of the work.” Obviously, you will be better off with more differences between your work and the original work.
5) What about fair use?
As I’ve said numerous times, fair use is a defense to copyright infringement. It will be raised in court after you’ve been sued, and the court will decide whether your work is a fair use. If someone thinks you’ve ripped off their work, claiming your work is a fair use probably won’t stop them from suing you. I’ve talked about fair use more in-depth here.
For a bit more-detailed explanation of copyright law, check out my post here.
 More information on fair use, Copyright.gov, https://www.copyright.gov/fair-use/more-info.html (last visisted August 29, 2017).