I have a continuing problem, and I would love some insight. I'm not alone in this, but I am one of the few who seem to care. To find a solution would be awesome. Thank you for looking though this, and for any hints.
To sum up, rendering to Photo-Jpeg (any resolution from any source) results in a considerable, easily-seen shift in color balance and gamma.
This was brought to my attention by another person back in late spring, 2014. I checked, and was aghast. It's not so much that you would necessarily notice it independently, but it sure can be seen if you compare the rendered file to the original.
It does not happen with other codecs, at least not the ones I use.
Contacted Adobe, submitted bug report, went back and forth a while as they didn't believe that I knew what I was doing (or that my machine was OK, etc), convinced them to perform tests, and got report back that they were able to replicate the problem, and that it would be fixed upon next release.
It's not fixed.
Quick procedure to test for yourself:
1. Import footage into comp, best use something with elements of blue, green, red, fairly balanced (makes the effect easier to see)
2. Render to Quicktime PJPEG, say 95% quality (higher than 95% is pretty much useless)
3. Import rendered result into comp, place on timeline as layer underneath original
4. Look at the comp viewer while clicking the original layer on/off
5. Note color/gamma shifts (brighter greens, less red, a shift in blue)
Proven by myself on two computers, both Windows 7 machines (otherwise I'd render to ProRes, but I can't since Miraizon ProRes yields noticeably soft results)
I specified that this happens with any source: Whether 4K Cinema DNG from FS700/7Q+, 4K AX100, GoPro, other renders, gradients generated from within AE ... it does not matter.
One of the machines (3 year old desktop, Windows 7 Home, i7-2600K Sandy Bridge 3.4 GHz CPU, 16GB RAM, GeForce GTX 560 Ti, separate disks for system, source media, render drive) is the one I originally worked with, to no avail. This machine is running AE CC Version 18.104.22.168 (not yet updated to the latest, and I'm not sure why not)
The other machine is a brand new laptop, Windows 7 Pro, i7-4790K 4 GHz CPU, 32GB RAM, GeForce GTX 980M, separate disks for system, source media, render drive - exhibits the exact same results. This is running the latest version of AE (I'm in render right now so can't get to the version number) downloaded and installed last night, March 3rd, 2015)
I do not render with Media Encoder. Not sure whether this will change anything - it was not suggested by Adobe. But for the sake of argument, I'll do a quick test to make sure while I finish typing this post - I do not expect it to be any different.
I shoot and render footage for stock video. My sources are varied, but mostly XAVC-S UHD from the AX100, ProRes and Cinema DNG from the FS700/7Q+, XAVC-S HD RX100m3, 2.7K GoPro, still sequences (RAW) from T2i and RX100m2, RX100m3. Also included are pre-renders from Vegas Pro when processing clips that need "work", so essentially I transcode from Vegas, import as PJPEG into AE.
Footage clips are processed with Vegas Pro 13 and After Effects CC. Sometimes both. Sometimes one or the other.
The effect of color shift happens whether I have any FX on or not.
Stock sites currently prefer, generally, either PhotoJpeg or ProRes. Again, I'd be stoked to use ProRes, but being on Windows, my only option to create PR renders is Miraizon, and my tests exhibit significant detail loss (especially noted in highly detailed shots, like with lots of trees, etc, which happens to be something I shoot a lot....renders with smooth gradients and flesh tones actually benefit form Miraizon softening)
PJPEG renders output from Sony Vegas do NOT show this color/gamma shift.
Miraizon renders from Vegas DO show the softening, even ProRes HQ, 4444, just like AE CC (and also apparently, Premiere Pro CC)
Initial discussion with some people still using older versions of AE indicate that PRE CC AE and Premiere do not have this problem.
The color shift effect does NOT happen when rendering, say, to h.264, but I do not do that, as I want my clients to have the best gradable footage, not some compressed delivery codec!
Has been suggested I render to Animation sans Alpha. Currently experimenting with that. Unknown if all stock sites will accept this for "normal" footage.
It has also been suggested that it is not a big deal, especially since many of my clips are "one-offs" that can be graded further to fit the needs of whatever project they end up in. But that's not the point....I also sometimes do import clips for work in AE, then export back to go into a timeline, and there the color shift is noticeable, when placed next to a similar clip that was not exported from AE.
If you made it this far, thanks!