The very short answer is that there are around 20 million "quality" pixels in a top-quality 35mm shot.
What this means is that a 5300 x 4000 digital camera would produce a shot equivalent to a scan from a quality 35mm camera
How many pixels in a frame of 35mm film?
A 1920x1080 HD signal is only 2 million.
Should be able to salvage enough resolution on old film to make a decent picture.