Removing gamma from profile

[Cipra]

Hello!

I have a couple of questions:

Question 1:
Is it possible to make a profile without gamma information, and only applying gamma to Gpu LUT?
If yes, how will photoshop and other color managed applications work with said profile? Will they completely skip correcting gamma and go straight to correcting colors? Will they simply do nothing? Will they correct gamma regardless even without the gamma info in the monitors profile?

Question 2:
Does novideo_srgb work with exclusive full screen?

Question 3:
Should I first turn on novideo_srgb to clamp my colors to the sRGB color space and THEN calibrate? Or the other way around?

Question 4:
Is it possible to do color corrections + clamp to sRGB + set gamma to 2.2 WITHOUT making a profile?
Like applying a LUT to GPU with these informations or something idk

I really want to clamp monitor to sRGB with a gamma of 2.2 without assigning a profile at all. Can DisplayCal do this?
I think dwm_lut can do it, but it costs some system resources and I think it doesn’t work in exclusive fullscreen ???? idk

[Vincent]

Hello!

I have a couple of questions:

Question 1:
Is it possible to make a profile without gamma information, and only applying gamma to Gpu LUT?

No, VCGT (GPU LUT calibration) is optional, but display profile should have primaries and nominal gamma, otherwise it will be useless.

If yes, how will photoshop and other color managed applications work with said profile? Will they completely skip correcting gamma and go straight to correcting colors? Will they simply do nothing? Will they correct gamma regardless even without the gamma info in the monitors profile?

Without TRC info Photoshop won’t know how display behaves.

Question 2:
Does novideo_srgb work with exclusive full screen?

IDNK.

Question 3:
Should I first turn on novideo_srgb to clamp my colors to the sRGB color space and THEN calibrate? Or the other way around?

Feed novideo_sRGB a full natibve gamut ICC profile with VCGT calibration, then let it calculate srGB simulation.

Question 4:
Is it possible to do color corrections + clamp to sRGB + set gamma to 2.2 WITHOUT making a profile?
Like applying a LUT to GPU with these informations or something idk

Using a fake synth profile. It’s like saying hey, this display behaves this way… but it will be useless if you can measure.

I really want to clamp monitor to sRGB with a gamma of 2.2 without assigning a profile at all.

That would be stupid. A profile is a description of display.

Can DisplayCal do this?
I think dwm_lut can do it, but it costs some system resources and I think it doesn’t work in exclusive fullscreen idk

Put your display in some preset that has native gamut, then use DWMLUT/AMDdriver/novideo_sRGB based on EDID/ICM profile from driver (native gamut, it’s “how display is supossed to behaved”, hence is a profile).
Then with this sRGB simulation loaded based on factory calibration, assign srGB as default display profile on OS, so browsers & photoshop will notice that your display behaves now as if it was sRGB.

[MW]

Does novideo_srgb work with exclusive full screen?

Yes, that’s it’s advantage over DWMLUT besides no performance overhead for GPU heavy apps.

[Cipra]

Thank you you two.

I really just want photoshop to fix my colors and NOT TOUCH the gamma.
the sRGB TRC is horrible and doesn’t reflect the monitor of my clients which are sRGB colors+2.2g

[MW]

Create your profile in DisplayCAL with tone curve:none. Don’t select install. Instead generate a synthetic ICC under tools-advanced. Select preset sRGB, change tone curve to gamma 2.2. Add the synthetic profile to windows color management as default display profile. Now in novideo_srgb select you DisplayCAL created profile. Choose Gamma 2.2 relative. In photoshop before export edit-convert to profile, select the synthetic profile from earlier.

[Cipra]

Wait. Applying it to both windows and novideo_srg. Won’t that double everything? Won’t photoshop read the profile set in windows -> apply it’s corrections -> then novideo_srgb will apply it’s correction on top. Leaving everything double corrected?
From what I gather novideo_srgb already clamps monitor’s colors to sRGB based on the primaries fed to it via an icc profile. And photoshop will also correct the colors displayed by reading the monitor’s profile set in windows. So wouldn’t doing both things make the image double corrected?
Shouldn’t I leave windows color management as default sRGB, and only do the srgb clamp through novideo_srgb?

Btw I found out online that novideo_srgb turns off whenever the screen goes to sleep, is that true? Is there a way to fix that, like adding an event or something in windows to reenable it automatically after every wake up?

[MW]

You would get double correction by installing the DisplayCAL profile while using novideo_srgb.

That’s why you provide a synthetic sRGB profile to the OS. novideo_srgb corrects colors to the standard you select so the synth profile lets the OS not to make further color transformations for sRGB source content.

Basically novideo_srgb has taken care it so you need to let the OS think you have a perfect sRGB display if that’s what you selected.

novideo_srgb survived restarts when I used it.

• This reply was modified 3 years, 7 months ago by MW.
• This reply was modified 3 years, 7 months ago by MW.

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