I think the 70mm film cels from willets designs came from the original internegative or at least a duplicate.

Jedi was the worst condition out of all three which is bizarre to say the least, while star wars may have looked a bit magenta sometimes, and empire had very good color.

What was the reason for the blow up to 70mm, only the vista vision effects would have been close to 70mm, while the rest was photographed on 35mm.

Was it because that way as a collectible you don't need a magnifying glass?

While printing the film to 70mm would increase and compound the grain issue prevalent on the several generations of optical effects used. Would also enhance the garbage mattes. Only the live action photography would benefit really.