If I were a better human being (not to mention a better hacker), I would
be able to retrieve this information from the Screen-L archives but...
  A while ago, someone posted information on how to determine whether a film
was in public domain -- some reference books, possibly a data base? Could
you please repost this information. I suddenly have developed a need to know
more about public domain films, where-as it was a subject of minor and casual
 interest at the time you posted this information before.
 
Henry Jenkins