That's super cool! I've digitized film as a hobby and for friends/family/small businesses, but not on that scale. I'm sure you love seeing all that old stuff come back to life in modern accessible formats too!

I (wrongly) assumed Poland wouldn't have as hardcore copyright laws as the US does, but yup, that's the case. That definitely makes sense though. You have to stay above board on who holds the rights even if it seems a little ridiculous at times.

It is extremely niche to researchers and historians. I know no museum is holding out with the hope that someone is going to come specifically for some random scanned images. People, even experts in the field, really don't care enough most of the time. Most archivists definitely would prefer to just throw it out (in an organized fashion of course haha) and let bygones be bygones.

Still, I've seen some places stay pretty overzealous on gatekeeping their archives. Random story, I worked for a university and their library had an enormously convoluted process to access their old, university specific, and mostly public domain photo archive. The people managing it are all in their 60s and 70s and would not budge that the super niche 120 year old photos MUST be protected. I worked in marketing and figured out which librarian to contact to have the lists of photo ID's sent over to me in high res when we needed some archival content. The rest of my coworkers just went to the index site, downloaded the low res preview with the watermark, and edited or cropped the watermark out. I couldn't convince them to just take the time to email the right person and get it in full quality, haha.