What is the best format for archiving digital movies? I work at a movie production company and we have a lot of film post production and release happening. All types of formats are handed to us by filmmakers and other studios. Now we want to archive all the files to a storage device and start moving them to LTO devices. What do you think is the best file format for storing the films? Note that the files are supposed to be ready to be accessed later for the purpose of preparing for screening and subtitling.
If you're looking for an open source codec that is finding favour in archives and museums as an archival format, you might want to look at FFV1 from the FFMPEG project.

https://en.wikipedia.org/wiki/FFV1

It is reasonably fast, reasonably efficient, cross-platform (including linux), free, and supports up to 16-bit per channel colour. Storage size is similar to ProRes.

However the main advantage is that it is 100% open source and non-proprietary, so it's not going to suddenly disappear come the Patent Apocalypse. It comes with ffmpeg, which is hands-down the best tool for doing these kind of conversions anyway.