zombie84 said:

TPM had all its effects work done at 2k, because 4k didn't exist in 1997, and every shot except one had a digital effect in it--meaning the negative of TPM will always be 2k (if it is from a stored DI in the computer) or less (if it is printed back onto film and then transfered beack to video). Probably all future releases will directly use the 2k DI though.

This may sound crazy, but if they still have the film, they could redo the effects at 4k if they want. Heck, if they still have the computer files, they can just rerender and recomposite. I know, it sounds crazy, but it is possible to make a 4k Phantom Menace if they have the film, even more if they have the visual effects files.