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April 8th, 2022 02:00
UP2720Q, ICC profiles for Linux or Mac
Hi,
I have the UP2720Q monitor which provides the self calibration feature. This seems to work well but I don't have any access to ICC-profiles after calibration/verification process is finished. Especially for the custom CAL1 and CAL2 slots.
There seems to be SW for windows called 'Display Color Management' which, as I understood it, is able to create ICC profiles after the calibration process has been finished. This however isn't available neither for Mac nor Linux.
I also had a look into the Dell SDK for Monitors, but this seems to allow me to control the monitor from the PC but there is no functionality to download any ICC related data from the monitor.
I know I could use a standard AdobeRGB ICC-profile and set the monitor to AdobeRGB color space, but this would be only a fallback option for me. I also could buy a colorimeter and calibrate my monitor using DisplayCal, but, because the monitor already has an built-in colorimeter, this isn't an option for me as well. Btw. there is no Windows far and wide.
So is there any way to retrieve valid ICC profiles for CAL1 and CAL2 slots for either Mac or Linux?
Thanks in advance,
Milosz
yumichan
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April 12th, 2022 01:00
1- They should be equal or very close, with measured values prefered over target valyes. ICC profiles tells color management engines how display behaves. If measured values are too off from target (as long as target is INSIDE native gamut), them embeded calibration system in theses dell won't be working properly and you'l need an external colorimeter.
2- No, because you may want a different gamma. For example this calibration target: native gamut, gamma/TRC = L* (if supported), D50 white. In this sitation EDID ICC will make photoshop render in a wrong way brightness of colors, since it expects display to behave with the TRC in EDID ICC (2.2 or sRGB typically) but display behaves with a L* TRC.
If you aim as calibration target to native gamut, and the same gamma as EDID TRC (macOS fakes it, it may not be EDID's) and whatever white, then you can use that default/EDID/built-in ICC. Image to screen rendering is always whitepoint relative, so it won't mind if EDID ICC says D65 but your calibration target is D50.... unless you try to use LUT3D software (don't use abs. colorimetric intent with that kind of whitepoint mismacth between EDID ICC and display).
yumichan
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April 11th, 2022 00:00
Use DisplayCAL and its tool "DisplayCAL-synthprofile" to create a synthetic profile that matches calibration target in UP2720Q OSD. Then apply that ICC profile as display profile in OS settings.
(Actually make 2, one for each CALx, since you'l have to switch them on OS Settings as you change OSD mode).
If you need xy coordinates for native gamut, use EDID coordinates, from File menu on DisplayCAL.
No colorimeter needed for these tasks
yumichan
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April 11th, 2022 11:00
If you need xy coordinates for native gamut, use EDID coordinates, from File menu on DisplayCAL.
If you are targeting to native gamut. It will create a profile, do not need to install it, maybe macOS created it auto when you plugged monitor 1st time.
Anyway, open profile info of that profile and look for iluminant relative XYZ cooords, or theyr xyY equivalent. XYZ is not xyz. xyY has the same Y as XYZ. Google about color coords.
EDID native info should be close to measured native gamut primaries. Otherwise firmware is lying or embebed probe is wrong. EDID white point & TRC (gamma) is expected to not be accurate, it's just a declaration about how display shoudl be out of the box.
Native primaries are native primaries, not your AdobeRGB/sRGB primaries after calibration.
FokaMokra
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April 11th, 2022 11:00
@yumichan Thanks for the info! I didn't know there is a way to create synthetic profiles. I suppose for the gamut x/y values i shall use the verification results, for example as provided in the Report-Tab of 'Dell Calibration Assistant' app.
I don't see any 'EDID coordinates' option in the file menu of DisplayCal. However I can create an ICC profile using the EDID data and view it's info in 'displaycal-profile-info'. Doing that there are entries like: EDID_red_x, EDID_red_y and so on. Is this the information you referring to? But those values do deviate from the results in 'Dell Calibration Assistant' quite much...
-Milosz
FokaMokra
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April 12th, 2022 01:00
Great. Thanks a lot for all the answers.
I think my problem is solved now
Edit: Read the whole thread. All posts from @yumichan are a solution, not only the last one.
-Milosz
FokaMokra
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April 12th, 2022 01:00
Hi @yumichan
just for clarification two last questions:
1. I mentioned before that I would use the verification result values as entries for 'displaycal-synthprofile', but in the end I think this is wrong. I should use the target (the monitor should be calibrated for) values instead, shouldn't I? As I understand those verification values are only for my information what the monitor is going to correct internally.
2. As the icc profile, generated directly from EDID, already stores the native gamut information then I don't have to synthesize an explicit icc profile *if* I want to drive the monitor in the 'native' color space. In this case I can just select the icc, from EDID, in my system and enable the 'native' color space in the monitor, right? With this setting I have the impression that my pictures do look fine and are not over-saturated as they used to be before.
-Milosz