Q. How can I tell if something is still under copyright?

It can sometimes be hard to know for sure if something is really in the public domain based on the date alone. Regardless of whether or not a work has a copyright notice (©), it may still be copyrighted if the copyright has not expired. There's no exact method to determine whether a work is in the public domain because the laws have changed many times in US history and it often requires tracking down a rightsholder to verify if they renewed their copyright if the work falls into a specific date range. 

While it’s true that no strings are attached to using public domain materials, you should be aware of certain potholes on the public domain highway... [From Stanford Libraries]

Just because something has no clear title, author, or published date doesn't mean it is without copyright either. Your version might be a copy of an original where that information was left out (like a recording from the radio using a cassette tape where no song title was introduced) or information may have been purposefully removed (like a screenshot of a film). Do a check to find out if the material has other information associated with it to help determine its origin and context (search by the lyrics, description of plot or actors in a film, and so on). Do not just assume things about material based on lack of information included with the physical material or that it looks "old" or "dated." 

See the links below to help you determine whether or not something is still under copyright, or how hard it might be to verify. If you still have questions, reach out to a TCC Librarian.