ChainsawAsh said:
Skyjedi, a blowup to 70mm wouldn't increase grain, as 70mm negative has a very fine grain structure. That's why the effects for Blade Runner and Close Encounters of the Third Kind were done with 70mm - so the grain wasn't excessive when compositing multiple layers of film.
I also doubt it would exacerbate the garbage matte issue, assuming the color timing was done correctly.
As long as the blowup was done from the original IP, a scan from the 70mm master negative would probably be the next best thing to scanning the original negative if that (somehow) wasn't an option (well, the original IP would be the next best thing, but, you know, barring that ... )
This isn't quite the same. Blade Runner had its effects shot in 65mm, so that the elements would be twice the resolution of the final composite. You want to start in the highest possible resolution because you know its going to get degraded.
Blowing up from 35mm to 70mm is a duplication itself, the reverse of the Blade Runner process. It does indeed add grain, because its a generation lost from the final negative; also, if the film is shot poorly, any flaw is magnified, and dirt and debris on the original negative is doubled in size. It's very different from shooting a film in 65mm.
However, Star Wars was photographed very cleanly, and most people don't realise that a well-shot 35mm film can be blown up to 70mm very easily without discernable quality degradation--in fact, I would say that this is the ideal format for many 35mm films (70mm also has six-track sound, making the experience all the better). This is very much like Imax films today--aside from The Dark Knight, there's never been a feature film shot in Imax size, they are all just regular 35mm negatives blown up to twice the size, and they look pretty good. I've never seen Star Wars in 70mm though, and I imagine a few of the optical shots would have looked pretty grainy since they already look rough in 35mm. But the general picture itself should be more than fine--70mm blow-ups were as common in the 70s as Imax is today.