After installing the upgrade, I watched the Christopher Reeve SUPERMAN on Blu-ray disc.
The movie has never looked particularly great on home video, not even in the latest DVD upgrade. This Blu-ray version was by far the best it's ever looked on home media.
The Krypton and Smallville sequences have always been soft and filtered looking, and even on Blu-ray, they still are. But once Clark gets to Metropolis, it's a sharp and bright as can be. I was very, very impressed with the picture resolution for the last hour and fifty minutes of the movie.