That sounds interesting! But if these are prints that were used in cinemas, isn’t there a risk that the quality of these prints has deteriorated due to frequent use and/or their age and/or poor storage?

One issue that also interests me is the references to the scans of “original negatives” that are often used to advertise films on Blu-Ray.
An example: On the Blu-Ray of the film Ben Hur (1959) it says: “Carefully restored frame by frame and digitally remastered using the original 65mm camera negative”.

But how is that supposed to work? For one thing, I wonder if this original camera negative (I assume it is the film that was in the camera during the shoot) is of the same quality after more than 50 years as it was back then. For another, I wonder how this is supposed to work. You use the original negatives, which surely have scenes on them that are not in the film (alternate takes, bloopers, etc.). Do you then have to re-cut the film?