Originally Posted by
Taranok
If you want to simplify it, it's the Mickey Mouse rule. If it's older than Mickey Mouse, it's public domain. If it's newer, it might be, but you would need to explicitly look it up. And it's called the Mickey Mouse rule because Disney is the primary motivator for extending the years on what is copyrighted specifically to protect their money makers, which started explicitly with Mickey Mouse. This is specifically for America and anyone with strong ties to America though, and international copyright laws might heavily complicate matters.