Here is some information im copying over from the avforums thread. There more for my benifit as the thread is quite long and full of de-rails. Some interesting information, its a shame some of the original links to articles are now down.
From the American Cinematographer story (Whole article Here) on TDK:
After shooting was complete, and after the editing process was well under way, DKP 70mm scanned select Imax takes at 8K resolution on a unique Northlight scanner. Then, Pacific Title and other facilities made 2.40:1 extractions from the 1.33:1 Imax negative to conform to the framing and movement decisions made in the Avid by Nolan and editor Lee Smith. That process resulted in a 35mm anamorphic negative, which was combined with effects shots and used to generate 35mm release prints.
To bring scenes shot in 35mm to Imax screens, where images are projected in 1.43:1, DKP 70mm scanned the 35mm interpositive at 4K, and an Imax team in Toronto applied digital DMR (Digital Remastering) processing to degrain and sharpen the images. The process stayed at 4K until the images were filmed out onto 65mm back at Keighley's facility and combined with the Imax material for print. The final Imax print combined the 4K DMR filmout, 5.6K and 8K Imax filmouts, and 18K contact prints from the Imax negative, says Keighley.
People suggested Chris and Wally should have covered themselves by shooting key sequences in both 35mm and Imax, but the 2.40:1 extraction from the Imax frame looks beautiful, he continues. In fact, due to the oversampling, it's probably the best 35mm anamorphic image we've ever seen. If we'd had time to scan the original negative at 6K, we could have produced even higher quality. The information is on the negative 35mm film captures the equivalent of 6K and a color bit depth of 14 bits plus.
As they did with the Imax prints of Batman Begins, Keighley and his team screened each of the 80 Imax prints of Dark Knight in real time to ensure quality. We're a small group of hands-on people who really care about images, he says. We pay attention to all the details all the way to the screen.
http://www.videography.com/articles/article_15888.shtml
"You also have to go in the other direction for the IMAX release. For these, the cut 35mm negative was color-timed at the lab [instead of a DI], producing an interpositive of the 35mm portions of the film. This went to IMAX, who used DMR—an IMAX-proprietary digital process—to 'blow up' the 35mm to the IMAX format. These scenes were then intercut with the IMAX camera negative. So, digital processes were used for the two format conversions, but each set of release prints was created by cutting the negative and timing the shots in a traditional manner."
It seems the concensus up to now is that that they used the IMAX version for the Blu. This version had 35mm blowups proberbly Edge Enhanched and corrected to the IMAX sequences, and then when put to BLU, another layer of EE and DNR was applyed. The EE and DNR are inconsistant through out the transfer.
http://gizmodo.com/5250780/how-regular-movies-become-imax-films
http://www.nxtbook.com/nxtbooks/questex/hom292114QPM/#/10
Courtesy: Mr. Torsten Kaiser @ blu-raycom
Having seen TDK tonight on the biggest IMAX theater screen Europe has to offer, I have to agree with RAH - the image is EXTREMELY interesting, indeed. To anyone, who has not seen the film in an IMAX theater, I would very much advise that you do. It is a truly amazing experience; especially the HONG KONG and the truck-under-the bridge sequences. I am truly impressed by the work at Framestore and Double Negative - they exceeded my expectations as to what would really be possible without "showing" in 8K by far. Perfect craftsmenship.
I can confirm that RAH's eyes were not getting the best of him re: the 35mm parts not being exposed full width. As far as I could determine, the AR is no wider than 1.90:1, in my book closer to 1.85.1. I will try to get the exact AR later next week.
And yes, I did notice some artifacting in very few shots on the 35mm PV material, ironically not in anywhere I would think SFX played a role. It may be that the stock was thought to be too grainy (although the VISION 2 is just excellent, thank you).
Re: Blu-ray discussion re: Halos/possible so-called "EE" and artifacts: While I want to wait a bit till I see the Blu-ray in its entirety (I saw merely bits and pieces as of yet and some of the capture flying around the web tied to all sorts of foregone conclusions and accusations) I can say this:
a) the grading of the HD master is not representing the image of the IMAX presentation, The Blu-ray has a tendency toward red (also in white), the IMAX presentation is stylistically very well balanced with fine cyan and pale yellowish tones,no red tendency at all, even the fleshtones are slightly orange.
b) the first shot of The Joker filmed from the back is framed on the Blu-ray with the feet cut but the top wide open. The original shot shows his feet almost to the ground and the skyline well centered in the composition. This, in my view, was not a good idea. It is, however, the only shot I remember from what I saw of the Blu-ray where this happend.
c) some of the shots on the Blu-ray (very few) were graded too "punchy" meaning the contrast was stretched too much in favour of losing detail in white. The shot inside the Gotham General Hospital (nice touch, by the way) with the cops roaming is one of them. This brings me to
d) and here is where I have Qs: is there anyone out there reading this with profound KNOWLEDGE and insight who can tell definitively HOW the Blu-ray master was assembled (i.e. from what) ?
The reason is this: As RAH (I think), I suspect that the IMAX 65mm image (very likely from data files) was used and reframed. If that was, indeed, the case, the problem re: "EE" stems not from any electronic "enhancements" at all, but is the result of a combination of photo-chemical issues (35mm PV 4perf blow-up to 65mm 15perf) and at least also digital issues (downconversion to HD level, with some troubles re: soft shots on the 35mm PV level). Here, it is possible that in some of those shots the decision was made to sharpen the image. This would have brought out the "ringing" that already exists on the photo-chemical level that is clearly evident even more. So, again, the so-called "EE" is, and that I can say for sure, NOT caused by the digital treatment, it is rather a result of what is already buried in the elements - provided, these datafiles were, indeed, used. Confirmation (or otherwise) would be very welcome. In the final analysis, what I have seen of the Blu-ray so far is mostly excellent, minus the color grading thing
I hope this helps draw a line under the "EE" issue that has caused a "war" at some other site...
"Shooting on IMAX posed some serious postproduction issues, too. Smith continued, "Chris really likes the look of film and the photochemical finishing process instead of a DI, so our post followed the traditional routeexcept for the IMAX negative, of course. Our goal was to keep the IMAX in its native format for the IMAX screenings. For the 35mm prints, the IMAX shots were digitally scanned and recorded to 35mm negative that was cut together with the 35mm camera negative. IMAX does this by scanning their 65mm negative at 8K resolution. Effects within the IMAX scenes were handled at 8K as well. These shots were then reduced to 4K resolution and recorded out to 35mm film. "
Wally Pfister oversaw the creation of the BD Version (panasonic kudo TV Used)
