dispcalGUI issue - perfect grayscale, wrong colors - AVS Forum
Forum Jump: 
 
Thread Tools
post #1 of 11 Old 08-30-2014, 06:08 AM - Thread Starter
Newbie
 
ONDr's Avatar
 
Join Date: Feb 2011
Posts: 9
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Liked: 4
dispcalGUI issue - perfect grayscale, wrong colors

Hi,

I'm having an issue with calibrating my LED Samsung display (SyncMaster P2250) with dispcalGUI.
I'm using i1 Display Pro colorimeter.

When I verify the results in HCFR grayscale and gamma is really good.
But for some reason the colors are way off.

Please check the attached screenshots.

I noticed that dispcalGUI is using many grayscale patches when calibrating but only few colored ones.
Maybe I need to use some other testchart...

Does anybody have an idea what I'm doing wrong?

Thank you.
Attached Thumbnails
Click image for larger version

Name:	hcfr_cie.png
Views:	45
Size:	388.6 KB
ID:	237002   Click image for larger version

Name:	hcfr_grayscale.png
Views:	36
Size:	79.0 KB
ID:	237010   Click image for larger version

Name:	hcfr_gamma.png
Views:	33
Size:	75.6 KB
ID:	237018   Click image for larger version

Name:	hcfr_references.jpg
Views:	33
Size:	74.0 KB
ID:	237026   Click image for larger version

Name:	hcfr_meter.jpg
Views:	30
Size:	69.7 KB
ID:	237034  

Click image for larger version

Name:	dispcalGUI.jpg
Views:	27
Size:	157.7 KB
ID:	237042  
ONDr is online now  
Sponsored Links
Advertisement
 
post #2 of 11 Old 08-30-2014, 12:22 PM
AVS Special Member
 
zoyd's Avatar
 
Join Date: Sep 2006
Location: Planet Dog
Posts: 5,041
Mentioned: 40 Post(s)
Tagged: 0 Thread(s)
Quoted: 454 Post(s)
Liked: 434
In order to do color correction (gamut mapping) of video sources you'll need to run a 3dlut using either software like MPC-HC/madVR as your player or external hardware like the eeColor box.

Last edited by zoyd; 08-30-2014 at 04:18 PM.
zoyd is offline  
post #3 of 11 Old 08-30-2014, 12:48 PM - Thread Starter
Newbie
 
ONDr's Avatar
 
Join Date: Feb 2011
Posts: 9
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Liked: 4
Oh I see... but if I create 3dlut it will be applied only to the madVR I guess. I'd like to have correct colors system-wide (in all applications).
ONDr is online now  
post #4 of 11 Old 08-31-2014, 12:19 PM
Senior Member
 
Tony359's Avatar
 
Join Date: Jun 2003
Location: Royal Wootton Bassett, UK
Posts: 249
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 34 Post(s)
Liked: 10
Hi all,

I'm very newbie when it comes to ArgyllCMS, I'm learning so my apologies for asking silly questions.
My first experience with ArgyllCMS is by running DispcalGUI on a projector, with good results I'd say.

My first silly question is: why I need MPC-HC to apply a 3dlut correction? What is the difference between doing it through the OS?

Thank you!
Tony
Tony359 is offline  
post #5 of 11 Old 08-31-2014, 12:50 PM
Advanced Member
 
spacediver's Avatar
 
Join Date: May 2013
Location: Toronto
Posts: 947
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 121 Post(s)
Liked: 75
I don't think windows supports 3dLUTs. The only way you can implement 3dLUTs is through applications that support them, such as MadVR.
spacediver is online now  
post #6 of 11 Old 08-31-2014, 03:14 PM
Senior Member
 
Tony359's Avatar
 
Join Date: Jun 2003
Location: Royal Wootton Bassett, UK
Posts: 249
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 34 Post(s)
Liked: 10
That makes sense.

So when I'm calibrating and profiling windows, what do I calibrate? What is the difference?
Tony359 is offline  
post #7 of 11 Old 08-31-2014, 04:29 PM
Advanced Member
 
spacediver's Avatar
 
Join Date: May 2013
Location: Toronto
Posts: 947
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 121 Post(s)
Liked: 75
A popular option is to adjust the display to meet grayscale and gamma targets, through the OSD, until you can't do any better, and then use your software of choice to generate a set of 1D LUTS which are loaded into the GPU LUT, and will workwork system wide (unless an application overrites the GPU LUT). These 1D LUTS can help fine tune grayscale and gamma.
spacediver is online now  
post #8 of 11 Old 08-31-2014, 04:46 PM
Senior Member
 
Tony359's Avatar
 
Join Date: Jun 2003
Location: Royal Wootton Bassett, UK
Posts: 249
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 34 Post(s)
Liked: 10
Ok, so the OS can only do a 1D lut, which is only calibrating gamma and grayscale. While a 3D lut can also do colour correction. Got it, that's why my gamut was never right, thanks.
Tony359 is offline  
post #9 of 11 Old 08-31-2014, 06:30 PM
Advanced Member
 
gwgill's Avatar
 
Join Date: Jan 2013
Location: Melbourne, Australia
Posts: 685
Mentioned: 7 Post(s)
Tagged: 0 Thread(s)
Quoted: 104 Post(s)
Liked: 88
Quote:
Originally Posted by Tony359 View Post
Ok, so the OS can only do a 1D lut, which is only calibrating gamma and grayscale. While a 3D lut can also do colour correction. Got it, that's why my gamut was never right, thanks.
Most Operating Systems (OS) support ICC profiles, which are much more flexible than a Video calibration.

Typically for software application use, you would calibrate the display (ie. by using 1D luts in the form of the 'vcgt' tag in a display ICC profile) to choose a brightness, white point and light response curve so that non-color managed applications will look OK, and then you would profile it as an ICC device profile and then install the profile in the OS. That way color managed applications know what the profile is for that display, and can then use the profile to convert colors into the correct RGB for that display. In this way the application can process any color in any colorspace it understands. Typically it understands what other colorspaces are using ICC device profiles. So the overall process a color managed application uses is to interpret an incoming color using one ICC profile and then convert it to the display RGB using the display ICC profile. This typically uses the CMM (Color Management Module) provided by the OS, but some applications use their own (ie. Adobe use ACE, ArgyllCMS has its own, lcms is used widely).

By comparison typical Video calibration is much simpler and less flexible. The source colorspace is assumed to be Rec709 + BT.1886, and either the display itself is adjusted so as to try and reproduce that colorspace, or a 3D lut (equivalent to a ICC device link) can be used to transform directly from the Video RGB space to the displays RGB space.
gwgill is offline  
post #10 of 11 Old Yesterday, 02:15 PM - Thread Starter
Newbie
 
ONDr's Avatar
 
Join Date: Feb 2011
Posts: 9
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Liked: 4
Hi,

After longer time I tried to calibrate my display again and create an ICC profile.
I generated profile with dispcalGUI, installed it on Windows and tried to use it with Firefox and GIMP.
Both of these programs support ICC and I could see it is working (verified with HCFR), but for some reason the colors are too off (again, but different way).
Blue is completely undersaturated which can be easily seen on pictures.
DispcalGUI report says that blue has deltaE 8.38!

I used Large testchart for LUT profiles, optimized for Gamma 2.2 with REC.709 primaries (D65).
Maybe I should use some other testchart.
Maybe my cheap display can't be calibrated more precisely... I don't know.

Please check the attached screenshots.
If anybody has an idea what might be wrong please let me know.

Thank you.
Attached Thumbnails
Click image for larger version

Name:	dispcalgui-LUT.png
Views:	3
Size:	74.6 KB
ID:	442834   Click image for larger version

Name:	coverage.png
Views:	3
Size:	39.9 KB
ID:	442842   Click image for larger version

Name:	hcfr-measurement.png
Views:	4
Size:	654.6 KB
ID:	442850  
ONDr is online now  
post #11 of 11 Old Today, 03:33 AM
Senior Member
 
fhoech's Avatar
 
Join Date: Apr 2013
Location: Stuttgart, Germany
Posts: 263
Mentioned: 11 Post(s)
Tagged: 0 Thread(s)
Quoted: 69 Post(s)
Liked: 51
It seems your display's gamut doesn't cover the whole of Rec. 709. This is probably a hardware limitation.
fhoech is online now  
Reply Display Calibration

Tags
colors , dispcalgui , gamut , hcfr , primaries

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page


Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off