Oh right, well we only get half resolution of blue and red due to the bayer mask anyway, which is how Cinderella was scanned, AND you lose resolution to the stuff outside of the picture area. Here’s an example of what resolution you would get if you did it at 2K:

Obviously that’s LATT LPP not one of my scans, but the principle is the same. The picture with is only ~1800 pixels at 2K and then you’re going to lose some more due to cropping, and to make it 1080p you’ll need to stretch it. For Academy films 1 2K scan would be sufficient for 1080p… but detail and grain structure are better preserved by scanning at 4K. 😃