What You Need to Know About Copyright:
- Copyright is immediate and omnipresent. In other words, as soon as a work is created and fixed in a medium of expression - written on a page, posted to the web, etc. - it is protected by copyright.
- Copyright lasts a long time. Copyright protection can last for decades after the original author has died. It can be a bit tricky to figure out when copyright expires but as a rule of thumb works created before 1923 are generally no longer protected by copyright. Once copyright expires works enter the public domain where anyone can use them. New works generally enter the public domain 70 years after an author has died. This Digital Copyright Slider can help you figure out if a work has entered the public domain.
- Some things aren't subject to copyright. Ideas, facts, short phrases, government works, and works created before 1923 are generally not covered by copyright and may be used by anyone. You can find some great free and open materials at Ohio State's Identifying United States federal government documents in the public domain page.
- Copyright law recognizes the special nature of educational use. Fortunately, since copyright is all about promoting the expression of new ideas, copyright law protects academic instruction with several important exceptions.
If you'd like to know more about the basics of copyright this Crash Course may be helpful. You can also read more about the basics of copyright in the Copyright Formalities FAQ