The good news is that Terminator Salvation, a movie that doesn't look too bad (I swear!) will be released to IMAX theatres. The bad news is that it wasn't shot on IMAX film originally.
From a recent interview with the director McG:
I wanted to shoot the film with this dead stock [old film that has been distressed to give the movie a desaturated look] . Therefore it wasn't conducive to shooting it in IMAX format. But we're going to bump it up to IMAX. We are going to bump it up, and it holds up very nicely, and it looks and sounds that much more impactful. But one price we had to pay for making those choices was that we didn't shoot in IMAX.
That's an interesting point about the film stock being a limitation. As I understood it, Terminator Salvation was shot on normal colour film stock that used triple the silver in processing to create a different look—but McG is saying that the source stock was distressed to begin with.
I'm not sure that we can use every development technique for IMAX film as we can 35mm, but even if it's possible, my guess is that price and convenience came into play when sourcing the movie on 35mm, too. [Sci Fi Wire]