Why you can use public domain images and movies
Copyright is just a temporary agreement. And although you really haven't needed to register your work with the U.S. since 1977, most people who are sincerely concerned with protecting their copyright, and if necessary, going to court to protect it, do. Just as it's always been since the United States began the Library of Congress, it starts with filling out paperwork. That paperwork is your *ticket to court* if someone infringes. But in the long run, you are making an agreement with the United States that someday your work will pass into the hands of the people, free and clear. This is, of course, long after you are dead, and if no one else has any right to your work (your heirs, etc.).
And so, every book, every piece of music, everything that is registered with The Library of Congress eventually makes its way into public domain. When the library was first begun, a copy of every book needed to be submitted to the library in order to get copyright protection from The United States. That's what began the library. Pretty clever, wasn't it? As you can imagine, that got to be a pretty big library - and it cost the young United States nothing to accumulate. They just had to build the library.
Our founding fathers couldn't imagine anything beyond a brick-and-morter library, of course, but they would understand how public domain works even today. This precious information is not only for the private use of a select few. It is for the people.
Use it. It's yours.
Posted by Brad Hall