I've always been curious about what it means for a movie to enter the public domain. A few years ago I sent a mail to Planet Money in what I thought would be an interesting hook but never got a response:

"Hi Planet Money, today is public domain day. I see that Fritz Lang's classic Metropolis is now in the "public domain." I was curious what that meant at a practical level for a German language silent film.

If Planet Money Movies wanted to release their own version of Metropolis, how would they do it? Can you just go to Amazon, buy the Blu Ray, and somehow release your own? What about the anti-piracy measures on the Blu Ray? What about the work that Transit Film did in restoring the film from the original negative? Does that count as some sort of newly original work? It's a silent film and a foreign film. How does the soundtrack and translation work?

If you have to make a new copy from the original reels, what if someone is hoarding them? Does that mean you could buy all the copies and prevent someone from releasing a public domain version?"

A work being in the public domain just means that if somebody claims that they have the copyright and sue you for distributing that work, you will prevail in court.

Restoration itself does not grant a new copyright. Other elements included in a restoration may be copyrighted e.g. new music or the graphic design of intertitles. A new translation is also copyrightable; essentially it's only the "original elements" that enter the public domain. Working around the anti-piracy measures of a blu-ray might be a crime, idk, but that's irrelevant to the copyright discussion; once you have a copy even if it came from an 'illicit' source, you're free to copy & distribute as you wish.

But yes, you need to acquire a copy first; if you can't find a work at all, how would you copy it, practically?

> If Planet Money Movies wanted to release their own version of Metropolis, how would they do it? Can you just go to Amazon, buy the Blu Ray, and somehow release your own?

Yes.

For example, wikipedia has a copy of Metrpolis and that's basically what happened

https://en.wikipedia.org/wiki/File:Metropolis_(1927).webm

Amazon Prime Video in fact has multiple low-quality versions of some films that have accidentally found their way into the public domain due to negligence of rightsholders, like John Wayne's McLintock!

> If you have to make a new copy from the original reels, what if someone is hoarding them?

This is a legitimate problem in public domain releasing. If you're trying to release a really good public domain version then you might need access to very high quality source materials. With a movie it would obviously be nice to scan the camera negatives. If the studio has those negatives in a vault, then you're cooked.

Didn't Bill Gates or some others buy up thousands of old artworks and put them on ice so they could paywall the scans?

>What about the anti-piracy measures on the Blu Ray?

In the US, bypassing DRM is a crime even if the intended use is legal. There are exceptions for things like criticism and accessibility, but I don't believe they'd be relevant.

Maybe it'd be as simple as selling your new copies as "for review purposes" and it'd be legal, I'm not sure.

> If you have to make a new copy from the original reels, what if someone is hoarding them? Does that mean you could buy all the copies and prevent someone from releasing a public domain version?"

This part at least, yes. A work being in the public domain doesn't mean someone is obligated to help you redistribute it.