Well, I'm currently researching a documentary film project about an old cinema (more of this to follow no doubt) and interested in finding some clips from feature films made between 1930 and 1970. Of course, I'm making this film off my own meagre dollar and looking for clips that I can use legally in my production for very few £££s.
My internet research dallied for a while in the realm of 'Public Domain' footage. Here's a Wikipedia page all about it including a list of films claimed to be in the Public Domain and supposedly not covered by copyright. One can even download most of these films and many others besides at the Internet Archive site.
It seems that the films on these 'Public Domain' lists are mostly ones in which the copyright wasn't renewed by the producers 28 years after the release dates of the films. For a while under US law, it seems that the non-renewal of copyright meant the films would fall into Public Domain use. Even under UK law, as recently as the 1988 Copyright Act, it seems that copyright on films had a 50 year expiry after the release date of the film.
For my project, this seemed ideal; Hollywood films from bygone days that I could cut up and integrate into my project... until I dug a little deeper....
Here's the catch... seems that UK law is quite different from US law on this subject and has changed very much for the worse. Nowadays, UK-based film-makers wont be able to source any film material this way at all, thanks to the 1996 Harmonisation of Copyright amendment to the 1988 Copyright Act. It seems that copyright of old films doesn't just fall away after fifty years of the film's release any more, oh no...
If you want to use old films, you now need to wait 70 years (until the end of the year) the director, producer AND writer of the film have all died! Effectively this legislation prohibits use of any extant old film footage in modern productions for way into the future. Not only that, but our film-making descendants will have a hell of a job working out the copyright status of any given film without finding the death dates of all the writers, directors, producers involved... Frequently, this will require extensive research into a huge list of hard-to track down characters. In short, the time period is too long to be of any creative use, and the multiple death-date system sets up a whole heap of trouble for the future. If a law was ever an ass, here it is.
By 1996 when this amendment to UK law came in, many old films had already out-lived the 50 year copyright period. Any film released prior to 1946 would have been available, plus all of those exceptional cases on the US lists too. The 1996 amendment has retrospectively over-ridden all of this; snatching back what was already out and kicking the rest into the very long grass.