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1. Re: Undocumented Color Rendering Changes in CC?
Noel Carboni Aug 19, 2013 2:04 PM (in response to ikonyc)Do you see the same issue when you set your Drawing Mode (in the Advanced GPU settings) to Basic and restart Photoshop?
There are two places Photoshop can do color-managment transforms - in the GPU and in the CPU, and setting to Basic (or disabling GPU operation entirely) moves it into the CPU, which traditionally has had fewer problems.
I'm pretty sure some work has been done in the area of GPU-based color-management in recent history. Not everything Adobe has changed is documented.
To this day (and going all the way back to at least CS5) I can reproduce a case where a smooth 16 bit gradient expressed in a document in the ProPhoto RGB color space will show up with banding and color. It doesn't happen with all color spaces. Notably ProPhoto RGB has the same gamma (1.8) as what you've mentioned.
See this for more info:
http://forums.adobe.com/thread/792332
The test file I linked there is still online.
I wonder if what you're seeing with your test document may be one and the same issue, but somehow having been triggered to show with your test dataset. Any chance you've moved up from Basic GPU mode to Normal or Advanced coincident with seeing this?
-Noel
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2. Re: Undocumented Color Rendering Changes in CC?
ikonyc Aug 19, 2013 2:39 PM (in response to Noel Carboni)Basic or Off solves the color problem. Turning OpenGL and OpenCL completely off cuts many features I reguarly use, so I'm setting it to basic. All settings on Normal have the problem. My previous configuration in CS was to advanced, so it is a change in CC/14.
Thank you very much.
KH
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3. Re: Undocumented Color Rendering Changes in CC?
Chris Cox Aug 19, 2013 2:48 PM (in response to ikonyc)Or it could be a bug in your video card driver.
Make sure you've updated the drivers from the GPU maker's website.
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4. Re: Undocumented Color Rendering Changes in CC?
ikonyc Aug 19, 2013 3:53 PM (in response to Chris Cox)Well, CC is pretty much unusable for me. I'm left with the choice of forcebly ingnoring non existant color errors or a curves interface which refuses to update either it's window or the screen in a timely fashion.
The card is an ATI Radeon HD5770 in a 2.4 Quad core mac running 10.8.4, nothing special there, and an NEC 2180 WG which has been fine unitl now.
I could change monitors and test, but until then, I'm back in CS.
KH
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5. Re: Undocumented Color Rendering Changes in CC?
Noel Carboni Aug 19, 2013 7:52 PM (in response to ikonyc)I guess you're using ColorMatch RGB as your document working space, given what you've written above.
Do you see the same issue if you change your working space to something else (e.g., Adobe RGB 1998)?
-Noel
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6. Re: Undocumented Color Rendering Changes in CC?
ikonyc Aug 20, 2013 7:41 AM (in response to Noel Carboni)FYI, in order to keep the file as perfect 256 steps, I'm not doing an conversions, just pasting channels and assigning profiles, and res'ing nearest neighbor. The file has been assigned Colormatch. If I reassign AbobeRGB and change my working space to Adobe in CS and CC, again, the composite color draws differently, while the channels draw perfectly (no stepping) and identically. Strangely, if I add an alpha, mulitchannel, assign CMYK, they draw the same. If I screen shoot on my secondary monitor, also running off the Radeon, on the file in Colormatch, again the RGB color composite is rendered differently in CS and CC.
There are tons of tests I could run on this, but I lost a day already thinking my monitor was messed. Under all circumstances on my machine (BW/RGB/Lab/4C), the single channels draw fine with a 1.8 gamma setting on the NEC (but not on 20%, etc).
It is hard to come to any conclusion other than Adobe has decided to render gamma/color differently in RGB via OpenGL/CL above the basic setting.
AdobeRGB assignments
http://www.ikonyc.com/CC_CS_bands_color_adobe_solar.jpg
CMYK assigments
http://www.ikonyc.com/CC_CS_bands_color_SWOP_solar.jpg
Next week I'll stick an Eizo CG220 on this system. If that doesn't solve it, I'll try installing a secondary video card. I'm not looking forward to setting up all my workspaces (PS, iD, AI) again after just doing it for Cloud. And remapping the intous. ETC.
Ken Harris
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7. Re: Undocumented Color Rendering Changes in CC?
ikonyc Aug 20, 2013 9:20 AM (in response to ikonyc)I previously said that turning down the graphics card settings caused the curves interface to be sluggish, but this seems to be a bug which is independant of the graphics card. If I add a point to a curve adjustment layer, and then undo, the image updates, but the curve window does not.


