Thanks for the compliment. Quite right, the Dolby color wheel is before the optical path. I would infer, then, that if the Barco didn't have a color wheel but instead a RealD ZScreen at the end of the optical path, that the ANSI contrast and MTF would both be affected? Also true that RealD does ghost busting encoding before the movie is sent to the theater. But from your previous post I don't think Dolby does any pre-encoding.
In this link you provided last May in this thread, Jim Slater talks with the Dolby3D folks about some of the technical details. I've re-read the article several times and I quote a few lines:
However, the Dolby 3D system has been designed so that a standard unprocessed' 3D movie file can be used, with any additional processing required for the 3D version being applied in real time in the Dolby Digital Cinema server during playback. Effectively, a process of compensation for any effects of the filtering on left and right eye images is performed in the server
, and an additional 1U high control rack is used to synchronize the operation of the filter with the projector and server. (Emphasis added.)
I asked how they ensure that all the necessary DCI colour parameters are complied with, knowing how stringently DCI applies its specifications, although there isn't yet a compliance testing procedure in place, and was told that there are agreed reference look up' tables which are used to ensure compliance.
I'm sure that thousands of eyeballs tested the Dolby system before it was released and if other demos have not shown hue issues, then something was wrong with the theater's Dolby3D equipment. Yet, it was a brand new install (less than 45 days) and without the glasses the snow-capped mountains were white (D6500, give or take), with the glasses they weren't the same color.
It would be interesting to hear from any Dolby people reading this thread as to a possible cause. I think Dolby3D is the better system but in at least one theater the artifacts are too apparent to ignore.