I am doing some workflow testing for a large HD project and have hit a snag. Sorry in advance for the long post, but the devil is in the details.
First my system specs: Mac 2x2.8 Quad Core, OS 10.5.8 10G ram.
Avid MC 4.0.2
Ok, on to it. I want to test color accuracy and quality for elements created in AE and passed to other systems.
To start I created a 1280x720 29.97 16 bit color comp (not color managed to start) with a black solid onto which I placed the basic 4-Color Gradient. I put a small scaling move on it.
I rendered this out with several codecs and brought them back into AE for comparison. The codecs were as follows:
tif image sequence
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?
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...
Hope this helps!
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