After getting a new monitor few days ago – ASUS PG329Q (10 bit + gaming) – I started my journey of calibrating a wide gamut monitor (previously only did it for 8 bit) and trying to understand what owning a 10 bit monitor really means.

I have run numerous calibrations, using DisplayCAL including 8 bpc and 10 bpc settings in nvidia control panel. I am a bit surprised that there is a quite negligeble difference in results – at least to my understanding – the percentage of coverage of sRGB, Adobe RGB and DCI-P3 are nearly identical for 8 and 10 bpc.  Is this expected or am I doing something wrong?

Expected. Coverage is given by LED backlight spectral power distribution, not by panel.

My results after calibration are at best like this for gamut coverage:

• sRGB: 99,6%
• Adobe RGB: 99,4%
• DCI-P3: 92,4%

Gamut volume is at 180%, 124% and 128% respectively. ASUS advertises 160% of sRGB colors and 96% of DCI-P3.

Does having a 10 bit monitor make any difference for calibration result numbers? Should I be using separate ICM profiles for calibration at 8 and 10 bpc, depending in which mode I am running (this changes based on refresh rate of the monitor, only 60 Hz so far works with 10 bpc, while I run games with 165 Hz).

With dithered ouput at app or at GPU HW output no real difference.

Without them, if monitor accepts 10bit input, even if panel is 8bit, you can use some app lack of features to let monitor handle the rounding error instead of the application, because if aplication goes down from 10 to 8 without dither before sending to GPU likely to cause some truncation errors.

People and vendors too usually mix “accepts 10bit input” with “10bit input at panel” with “true 10bit panel”. They are different depending on who has the responsibility to truncate : app, monitor HW, monitor panel… although if properly done results are interchangeable on SDR contrast windows (256 step can cover that kind of window with dithering).

• This reply was modified 2 years, 9 months ago by Vincent.

Because wrong truncation in PS, not because it was needed.

Switching to Microsoft ICM you get some cleaner grey, but tints are still visible. You also see them in browsers and viewers, this is general problem in Windows. But, being plugged in Macbook and calibrated, 8-bit display shows clean grey. Here is the same thing, Vincent: we may talk on theory and tech aspects, but 10-bit gives practical advantage to Windows users by now.

Opinion: I show this effect to photographers and describe how to check gradients purity, – totally switch off ICC usage in two steps: flash vcgt in Profile Loader and use “Monitor RGB” proof. It’s important for B&W and mixed studio shots, commercial design and design over photo (popular in product photography) as well. This take no sense in real world colour photos.

OK, Vincent, but what do you think on signal type syncronization? I don’t mean composite, YCbCr etc., but the effect of data type and derivative adaption of hardware workflow. By example, I have already described the flaw with weak black at some horizontal frequencies. Could similar thing happen with vcgt (2provanguard: videocard gamma table) dithering on/off/level? My experience tells me that 10bit displays realy draw better grey in Photoshop and this happens even with nVidia cards, though 10bit displays are seldom items here.

It is no display related as I said. It’s because the whole chain:

Photoshop:

processing (GPU basic vs accel) -> truncation to interface driver  -> openGL vendor driver -> (1) LUT -> output (dither/no dither) -> phys connection -> display input (8/10)-> monitor HW calibration/factory calibration/calibration with OSD) -> dithering to panel input -> panel input (8/10) -> (optional dither) -> actual panel bits.

LR/ACR on Photoshop/C1:

Processing -> truncation with temp dithering -> Windows composition at 8bit -> (1)

GIMP / In design  / Ai / firefox /others:

Procesing -> truncation to win composition iface -> (1)

If display has no banding non color managed, color managed banding  is ONLY caused by steps before (1).

Photshop chose to do it in the “expensive way” (before gamer Geforces and Radeon), requiring 10bit hook opn OpenGL and 10bit end to end pipeline because GPU vendor needs, before taht “casual 10bit driver” people had to pay for Quadros and Firepros for task that do not require such high bitdepth end to end (others do, but no photo SDR work).

Apple know the trick and with RGB8888 (I do not remember name) pixel format they provide hook for 10bit input, although they will truncate with temp dithering on GPU, out of PS scope

Also Adobe for other tools chose to do it the RIGHT WAY: processing output dithering to whatever windows composition it has. 0 banding if non color managed the monitor have no banding.

Also Adobe for other tools chose to do nothing: truncate to win composition to 8bit: Illustrator/Indesign, which is a shame because syntehics gradienta are common tools there.

If you have issues with PS is
-poor driver implementation: basic GPU on 8bit seems to cause less issues since no simplified color management is done by GPU)
-poor PS implementation (open the same image with Adobe Camera raw filter in PS… banding is gone in 16bit images)

and none if this is related to 10bit advantage end to end on SDR contrast windows.

Hm, why do you call it dithering? I know the thread with nVidia hack, but is the effect described anywhere for programmers?

Temporal dithering. It works auto in AMD cards (related to 1DLUT output) and in ACR/LR/C1. It is done by default, user need to do nothing.

@provanguard

As said by Alexei IPS/VA & good uniformity. Since you have a newer GPU model you can get one with 10bit input (whatever panel it has behind) so only for Photoshop you can get rid of colormanagement simplifications done in that app (truncation of processing to driver interface with no temporal dithering).

Also since you want a gamer display those new 165Hz 27″ QHD or UHD are usually P3 displays, some of them do not have gamut emulation capabilities so for gamer all will look “wrong” oversaturated… but you can look at @LeDoge DWM LUT app , works like a charm.
Look carefully at monitor manual to spot those gamer models that DO NOT HAVE sRGB mode, or by review if such OSD is locked at high brightness.
Anyway DWM LUT works fine if display lacks of sRGB mode.

• This reply was modified 2 years, 9 months ago by Vincent.

ICC with GPU calibration and DMW LUT “can be” mutually exclusive, depending on VCGT.

Use DisplayCAL and calibrate display at native gamut to your desired white. Install it & etc.

Then if you wish a LUT3D for DMW LUT:
-Open LUT3D maker app in Displaycal folder
-source profile: colospace to simulate
-target colorspace: diplay colorspace
-Create LUT3D

If you wish to calibrate grey using DWM LUT because your card don’t dither or do not make it properly or because you want to, “apply VCGT” to LUT3D when you create it. BUT if you do this you cant have displaycal profile as display profile in OS. Assign as default profile in PS the ICC of colospace to be simulated.

It’s like Resolve LUT3D for GUI monitors, you have to choose who is going to calibrate grey, 1DLUT in GPU HW or LUT3D in software.

For non color managed apps if you rely on ICC to gray calibration, no need to change it on OS, LUT3D won’t have VCGT applied.
But for color managed apps things will look bad, mostly desaturated.
If you wish a full  native gamut LUT3D to native gamut ideal colospace look on DWM LUT thread here, explained. The concept it’s easy, make a synth profile that represent your idealized display. Assign it to OS default display. PS & LR & Firefox will color manage to that profile but calibration is donw through DWMLUT, no through 1D GPU LUT.

• This reply was modified 2 years, 9 months ago by Vincent.

Apply Calibration (vcgt): UNCHECKED  (Is this correct?)

Rest are default values.

If you wish to calibrate grey using DWM LUT because your card don’t dither or do not make it properly or because you want to, “apply VCGT” to LUT3D when you create it. BUT if you do this you cant have displaycal profile as display profile in OS.

Well, I do have the profile created using DisplayCAL loaded and active, so I did not use “apply VCGT”.

If your GPU causes banding you can check use VCGT, and assign as default display profile a synth version without VCGT. Explained  bellow

Assign as default profile in PS the ICC of colospace to be simulated.

Is this only specific to PhotoShop?

I meant “OS” not “PS”, control panel\ color management, PS is a typo :D. To not mess with Photoshop color options if you do not know what you are doing.

For non color managed apps if you rely on ICC to gray calibration, no need to change it on OS, LUT3D won’t have VCGT applied.

From here forward I am a bit lost.  How can I rely on ICC if an app is not color managed?

VCGT is grey calibration, embebed into disoplaycal ICCand loaded into GPU.

If you wish a full  native gamut LUT3D to native gamut ideal colorspace look on DWM LUT thread here, explained. The concept it’s easy, make a synth profile that represent your idealized display. Assign it to OS default display. PS & LR & Firefox will color manage to that profile but calibration is done through DWMLUT, no through 1D GPU LUT.

I would like to try that. I would require a noob level instruction, please

Go to displaycal folder, open synth profile editor. Make a synth profile with the same white, and red, green and blue primaries coordinates (illuminnst relative xyY data on profile info in displaycal) and same nominal gamma. Usually you want to play teh “infinite contrast tick” (black point compensation) on both profiles.

Then make a LUT3D with that sytn profile as source colorspace, target your displaycal profile with VCGT caibration.
Resulting LUT3D is close to a monitor with HW calibration calibrated to native gamut, hence perfect for PS or LR or other color managed apps.

Assign synth profile as default display profile in OS (control panel, color managemen , device tab). Open DWMLUT and load LUT3D. This way you can get no banding even with intel iGPUs, unless VCGT to be applied is to extreme to be simulated with 65 node per color ramp.

Games will look oversaturaed (native gamut) but for PS or LR os like yu had an Eizo CS with HW calibrayion and idealized ICC profile (matrix 1xTRC) than minimized banding caused BY color management app.

• This reply was modified 2 years, 9 months ago by Vincent.