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1. Re: Funky Banding Seen in PS CS5 Color Management with Some OpenGL Modes
Chris Cox Feb 16, 2011 12:56 AM (in response to Noel Carboni)Hmm, looks like the shaders (that handle profile conversions in normal and advanced) aren't doing something quite right there.
We'll have to look into it.
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3. Re: Funky Banding Seen in PS CS5 Color Management with Some OpenGL Modes
Chris Cox Feb 16, 2011 1:02 AM (in response to TerryBarriff)If I enable my monitors colour profile on the home PC, white turns into a cream colour!
That means that the profile doesn't actually match your display, the profile has a different white point.
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4. Re: Funky Banding Seen in PS CS5 Color Management with Some OpenGL Modes
TerryBarriff Feb 16, 2011 1:19 AM (in response to Chris Cox)So if I were to set my monitor to the colour profile and enable the colour profile within Photoshop, it should be ok?
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5. Re: Funky Banding Seen in PS CS5 Color Management with Some OpenGL Modes
klsteven-qW1idA Feb 16, 2011 3:33 AM (in response to TerryBarriff)I tried it on my system (NEC PA 241W and GTX470). My monitor profile was made with Spectraview 2. I see no difference between OpenGL on and off.
I then set my proof to "Internet Standard RGB (sRGB)". No I can see very slight banding with OpenGL on. But by far not as bad as in the sample Noel showed.
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6. Re: Funky Banding Seen in PS CS5 Color Management with Some OpenGL Modes
Noel Carboni Feb 16, 2011 6:25 AM (in response to Noel Carboni)Thanks for the responses, and thank you, Chris!
Just to clarify (I know Chris understands, but some of the other responses don't list the OpenGL mode)...
I see the problem:
- With OpenGL Enabled in Advanced mode.
- With OpenGL Enabled in Normal mode (i.e., what's shown when you click the [Advanced...] Button in Edit-Preferences-Performance.
I don't see the problem:
- With OpenGL Enabled in Basic mode.
- With OpenGL Disabled.
-Noel
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7. Re: Funky Banding Seen in PS CS5 Color Management with Some OpenGL Modes
Noel Carboni Feb 16, 2011 6:27 AM (in response to TerryBarriff)Terry_cy1, I strongly recommend going and finding references on how color management works. It's not something that can be given a simple answer.
-Noel
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8. Re: Funky Banding Seen in PS CS5 Color Management with Some OpenGL Modes
TerryBarriff Feb 16, 2011 6:28 AM (in response to Noel Carboni)Sorry Noel,
I got carried away with colour profiles and didn't state that I had tried all three and got the same results as you
Terry
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9. Re: Funky Banding Seen in PS CS5 Color Management with Some OpenGL Modes
Noel Carboni Feb 16, 2011 6:39 AM (in response to TerryBarriff)No problem, and thanks for the follow-up.
The most viable workaround at the moment, if you're seeing the same issue, seems to be to go into Edit - Preferences - Performance, click the [Advanced] button, and set OpenGL to run in Basic mode. You still get all the OpenGL-specific features but the color transforms appear better.
In normal use this may just show up as a slight display inaccuracy; I'm not sure if it would be enough to lead people to make any wrong processing decisions. It doesn't appear to affect the document quality at all.
-Noel
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10. Re: Funky Banding Seen in PS CS5 Color Management with Some OpenGL Modes
klsteven-qW1idA Feb 16, 2011 8:05 AM (in response to Noel Carboni)Noel,
just to clarify: I used the advanced mode.
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11. Re: Funky Banding Seen in PS CS5 Color Management with Some OpenGL Modes
Noel Carboni Feb 16, 2011 8:44 AM (in response to klsteven-qW1idA)Thanks. That seems to imply it's at least partly profile-dependent.
-Noel
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12. Re: Funky Banding Seen in PS CS5 Color Management with Some OpenGL Modes
Hudechrome Feb 16, 2011 9:07 AM (in response to Noel Carboni)Since it is an Open GL Problem, I assume you don't see it in a print, correct?
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13. Re: Funky Banding Seen in PS CS5 Color Management with Some OpenGL Modes
Noel Carboni Feb 16, 2011 9:18 AM (in response to Hudechrome)Excellent question. I shall try a test print. Edit: It printed perfectly smoothly.
Did you try opening the image I posted (it's small)? Do you see the slightly colored posterization/banding on your screen?
-Noel
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14. Re: Funky Banding Seen in PS CS5 Color Management with Some OpenGL Modes
Chris Cox Feb 16, 2011 10:11 AM (in response to Noel Carboni)That seems to imply it's at least partly profile-dependent.
Yeah, it probably has to do with how the profiles are concatenated into a table for application in the shader, or something off in the shader interpreting the table.
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15. Re: Funky Banding Seen in PS CS5 Color Management with Some OpenGL Modes
Hudechrome Feb 16, 2011 10:23 AM (in response to Noel Carboni)I saw the banding. Since I am also profiled with PtoPhoto, I switched to sRGB to examine it and saw the slight banding. It is really obvious if I open it with ProPhoto!
I have to go pick up a car so I'll run the test itself here later.
Cheers!
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16. Re: Funky Banding Seen in PS CS5 Color Management with Some OpenGL Modes
Noel Carboni Feb 16, 2011 10:27 AM (in response to Chris Cox)Thanks for the additional info. It seems like something minor that one might never notice and could live with for editing real images, though folks desiring 30 bit displays might be disappointed with this level of inaccuracy.
Ah well, for the moment it seems I've found a good, solid reason to choose a particular Advanced OpenGL setting - Basic. I hope Photoshop is as stable with this choice as it has been for me set to Advanced.
If there's any further information I can provide, don't hesitate to ask.
-Noel
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17. Re: Funky Banding Seen in PS CS5 Color Management with Some OpenGL Modes
jeharrisAdobePS Feb 16, 2011 12:15 PM (in response to Noel Carboni)If you see it on AMD but not on Nvidia, it is most likely a case of the hardware bilinear interpolation precision being too low on the AMD side. AMD drops the floating point range to 24 bits or so, while nvidia keeps it at 32 bit floating point. Just guessing, so we will investigate this issue.
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18. Re: Funky Banding Seen in PS CS5 Color Management with Some OpenGL Modes
Noel Carboni Feb 16, 2011 2:12 PM (in response to jeharrisAdobePS)Lawrence (Hudechrome) above has a nVidia card, I believe.
By the way, I think it's quite slick that you have color management code working on the GPU (okay, very nearly working). Bravo!-Noel
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19. Re: Funky Banding Seen in PS CS5 Color Management with Some OpenGL Modes
Hudechrome Feb 16, 2011 3:39 PM (in response to jeharrisAdobePS)I am running the nVidia 9500 GPU set.
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20. Re: Funky Banding Seen in PS CS5 Color Management with Some OpenGL Modes
jeharrisAdobePS Feb 16, 2011 3:42 PM (in response to Hudechrome)Thanks for the info, it helps us narrow down the issue!
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21. Re: Funky Banding Seen in PS CS5 Color Management with Some OpenGL Modes
Hudechrome Feb 16, 2011 3:48 PM (in response to jeharrisAdobePS)I'm also running Advanced>Normal with the Open Gl settings, at a cache level of 1024, if that matters.
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22. Re: Funky Banding Seen in PS CS5 Color Management with Some OpenGL Modes
Hudechrome Feb 16, 2011 3:58 PM (in response to Hudechrome)I just did a gradient test myself here, black to gray 16 bit
with the above settings in Open GL, ProPhoto rgb, and while I found banding, there is no color shift
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23. Re: Funky Banding Seen in PS CS5 Color Management with Some OpenGL Modes
Noel Carboni Feb 16, 2011 4:06 PM (in response to Hudechrome)Please try opening the very same .PSD file I posted above, just to make sure. It's in a link at the bottom of my first post.
-Noel
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24. Re: Funky Banding Seen in PS CS5 Color Management with Some OpenGL Modes
Hudechrome Feb 16, 2011 4:22 PM (in response to Noel Carboni)That's what I did the first time, Noel. I cpoied the image from the post, pasted it in File> New, twice,setting it first as ProPhoto for the color space, then sRGB, as I assume that may the color space from the post. In either case, I saw the color in the banding, with ProPhoto being the most obvious.
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25. Re: Funky Banding Seen in PS CS5 Color Management with Some OpenGL Modes
Noel Carboni Feb 16, 2011 4:32 PM (in response to Hudechrome)You're missing the point.
Download the ZIP file I posted a link to. Inside it is a .PSD file. Open that.
http://Noel.ProDigitalSoftware.com/temp/TestGradient.zip
-Noel
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26. Re: Funky Banding Seen in PS CS5 Color Management with Some OpenGL Modes
Hudechrome Feb 16, 2011 9:54 PM (in response to Noel Carboni)I didn't miss the point, but I did miss the link!
That link won't open. I get an error message from zip:
"Extracting to "C:\Users\Hudechrome\AppData\Local\Temp\wzfb91\"
Use Path: yes Overlay Files: yes
Central and local directory mismatch for file "TestGradient.psd" (crc-32 - local: A2E869D3 hex central: 9BAC0CCC hex).
Local and central CRC values don't match."I tried placing it in a different folder, no dice.
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27. Re: Funky Banding Seen in PS CS5 Color Management with Some OpenGL Modes
Chris Cox Feb 16, 2011 10:15 PM (in response to Hudechrome)Hmm, I didn't have a problem downloading and unzipping it.
(and we've got several people looking into the problem now)
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28. Re: Funky Banding Seen in PS CS5 Color Management with Some OpenGL Modes
Hudechrome Feb 16, 2011 11:26 PM (in response to Chris Cox)I tried downloading it twice.
Apparently some sort of parity check error, which a google search described as unrecoverable. If the error is here, it isn't an anomaly.
At any rate, generating the radial did not produce the problem on my system.
Are you able to reproduce it directly or is it necessary to reference Noel's generation of the radial gradient?
Message was edited by: Hudechrome
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29. Re: Funky Banding Seen in PS CS5 Color Management with Some OpenGL Modes
klsteven-qW1idA Feb 17, 2011 1:27 AM (in response to Hudechrome)Since we are talking about colormanagement and GPUs I may point to some other bugs:
1. If you have an LAB image and go to one of the fullscreen modes (F), you get a massive saturation boost on screen, if OpenGL is enabled. I see this on a PA 241W and a GTX 470. Just a guess: Since I don`t see it on my secondary monitor (Eizo S1931), maybe the monitor profile is just not taken into account. This would be easiliy noticable on a wide gamut monitor like the NEC, but hardly on a "normal gamut" monitor like the Eizo.
2. If you go to the "convert to profile" dialog and convert to the same profile as the current one (sRGB to sRGB or Adobe RGB to Adobe RGB, although I know that this makes absolutely no sense), you get a saturation shift, if "Preview" is turned on and Open GL is used! As soon as you actually click "OK" the shift is gone,because no conversion was done, of course. So this is only a cosmetic bug.
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30. Re: Funky Banding Seen in PS CS5 Color Management with Some OpenGL Modes
jeharrisAdobePS Feb 17, 2011 5:50 AM (in response to klsteven-qW1idA)To the best of my knowledge the 1st one is being tracked. Will check with our QE.
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31. Re: Funky Banding Seen in PS CS5 Color Management with Some OpenGL Modes
Noel Carboni Mar 23, 2011 9:03 PM (in response to Noel Carboni)By the way, this exact same problem manifests on my new ATI Radeon HD 5670 as well.
-Noel






