Assuming copyright laws don’t change by then, otherwise there is no way to know.
A plausible answer is 1977 (when the film was released as Star Wars) + 95 years (for pre-1978 works) = 2072. However, the film had been edited by George Lucas for the 1997 “Special Edition” release. Does this mean that I cannot publicly play the Special Edition VHS tape I have at home in 2073 and have to wait until 2092, or 70 years after GL’s death?
George Lucas has been infamously attempting to erase copies of the original movie. Therefore, no HD home video release for the 1977 film exists, however, a fan effort known as the “Despecialized Edition” compiled different versions of the movie from various sources, patching the Special Edition 4K Blu-ray rip to try to replicate the original 1977 experience. Does this legally questionable version enter public domain in 2072, or does this only apply to official (SD) releases?
Attorney here.
The original version of A New Hope should enter the public domain in 2072.
The Special Edition of A New Hope should enter the public domain in 2092.
The despecialized edition uses work from the special edition and would not be legally distributable until at least 2092. But as to your question on resolution, I do not believe copyright law would differentiate between a work bases solely on the published resolution. As the other comment suggests, A high res scan of the original A New Hope, if it exists, would be in the public domain in 2072.
Interesting… Too bad a right-holder can do minor edits to their work and effectively extend copyright (which is already very long in my opinion) if they nuke the previous version. Lucas was surprisingly successful at that, and I think game studios or other creators could do that today too with their aggressive DRM tactics.