To compare, I placed the imported files on separate layers above my original image. A rectangular mask was placed on the imported layer in the middle 50% of the image to allow a quick visual comparison. An adjustment layer was placed at the top of the comp with a curves effect set to crush the gamma to amplify any differences. I also did a difference matte comparison between the imported and original element.
The results were disappointing at best. In order of good to bad with respect to levels the list was:
tif image sequence - imperceptible level difference, perceptible banding increase on some areas.
avid1-1x - imperceptible level difference, much greater banding increase on the whole image (almost as if it were not 10bit).
dnx220x - perceptibly darker overall, banding similar but in different areas than original.
dnx145 - perceptibly darker overall, banding a bit more severe.
proresHQ and prores - significantly brighter overall (something must be wrong!), could not tell banding difference to due brightness increase.
Looking at the difference matte showed some interesting results, but as I am not totally comfortable in what it is telling me yet, I will ignore that for now.
But to the heart of the matter. Why are the ProRes levels so far off? I did some web searching and based on that I turned color management on to Rec 709 for the project and interpreted all imports as Rec 709. No difference.
I feel I must be doing something wrong in my workflow here. Any insight?
Re: workflow problem by Mark Walczak on Nov 25, 2009 at 5:51:55 pm
This seems like a pretty advanced post - well over my head. You may want to post this over at fxguide (http://www.fxguide.com). I know that Stu Maschwitz is heavily involved with color profiles/etc, so you may want to stop by his site (http://prolost.com/) and shoot him an email...