Amazing technical write up on how The Dark Knight was filmed and worked on in Post.
Studio Daily Article on The Dark Knight Production Process.
In short, IMAX breaks the technology that is at hand for most movie production studios, even the big ones. Well worth the read.
To support the IMAX scenes, the studios could not work in full IMAX resolution, which is theoretically 18K; instead, the target resolution was approximately 8K, the maximum resolution for scanned film. Even that was difficult. “A single 8K frame requires 200 MB of data,” Franklin says. “So we had to upgrade our whole infrastructure. We needed faster network speeds to move data around, massively beefed up servers, and — the most important thing — a new compositing solution.”