Congratulations! You've just composed a musical work. / You are a poor college student who wants to copy lots of music from the library instead of buying your own copies. / You are a faculty member wanting to use music in your classes and that whole Fair Use thing is gibberish. / This Librarian admits that she is often confused by copyright as well.
This page will list a few basic facts and provide several links to help you figure out if you're breaking the law or not. Copyright is very serious, and you must adhere to the law. If you're caught breaking the law, composers and their representatives can take legal action that will make your tuition payments look like tooth fair money! Plus, it's just wrong to ignore copyright, and as musicians, we should respect each other enough to buy music when it's appropriate to do so.
1) Compositions published in the US before 1923 are Public Domain (PD). That means you can copy until you run out of paper and toner. These works are represented in IMSLP (the Internet Music Score Library Project), which is a great source for finding and printing music scores.
2) Compositions published in the US after 1978 are protected for 70 years AFTER the composer's death. They are protected for 95 years if published by or if copyright is owned by a corporation. Basically, if something was written after 1978, it's almost definitely under copyright protection, unless the composer released the rights to a creative commons license. You need to be very careful with post-1978 music, especially in a public setting.
3) Composers have the right to terminate copyright contracts 35 years after the granting of the copyright or date of transfer. This is in case the composer got a bad deal with a publisher or record label.
4) There are particular rules regarding "cover"ing a music work. Make sure you're familiar with them before choosing to perform somebody else's work, especially if it involves a visual component, like movie soundtracks, video games, etc.
5) Be very careful of Public Peformance rights. Make sure you have acquired the appropriate licenses from licensing agencies before performing a copyrighted work or showing a copyrighted movie in public.
The information contained on this page is courtesy of Cari Alexander, head of the music/media library at TCU. Thanks, Cari!