MadVR for P3 display?

[MaxLt]

I have two displays I'm trying to get the colors right for. Please let me know if I'm doing it right or not:

1. Display calibrated to do the perfect P3 with 2.2 Gamma.

I apply ICC profile for P3 in system settings (Windows 10) and in MadVR I set the setting that the Display is already calibrated and pick P3 with 2.2 Gamma as the target. Simple enough.

My understanding is that MadVR disregards system ICC profile, so the image is NOT corrected twice (by MadVR and then by Windows) or anything like that. Is that correct?

2. Display with 86% of P3 gamut is calibrated to be as close to P3 gamut as possible with 2.2 Gamma.

Right now it's calibrated the same way as the previous display, except with not the P3 but display-specific ICC profile in system settings. But my understanding is that this leads to colors in MadVR being desaturated too much because MadVR assumes it's full P3 gamut display while it's not quite there.

Is there a way to adjust for this? Can I use the display ICC somehow or do I need to produce a custom calibration file for this display?

Thanks!

[Asmodian]

1. Sort of, madVR does not discard the ICC profile but the image is not corrected twice. In any mode but windowed overlay madVR outputs the same as any other program so the output is corrected by the profile loaded into the GPU hardware LUTs like everything else. In windowed overlay madVR copies the values from the LUT and applies them itself in order to maintain the correct output. I assume your "ICC profile for P3" has linear LUTs so this probably does not actually affect the output at all in your case. This is exactly what you want in this situation because it is usually the ICC profile that fulfils the "already calibrated".

edit: A clarification might be needed here. Windows is not gamut aware and always assumes you have a sRGB display, it only uses linear LUTs from the ICC profile which correct the white point and gray scale. This means that in Windows only color managed applications use the ICC profile to do a full gamut conversion and madVR is not actually color managed in this way. madVR cannot load an ICC profile and use it to do a gamut conversion, it can only use its internal conversions or a 3DLUT (or yCMS) for gamut conversions.

2. You will need to use a 3DLUT to get correct output on any display that doesn't match one of the options in "this display is already calibrated". The easiest way to get a 3DLUT without spending a lot of money is to use DisplayCal but you will need a colorimeter or spectrometer. Once you figure this out, and if you have a good meter, you may want to try a 3DLUT for the display that is nominally perfect P3 too. Nothing is ever really perfect and in my experiance a 3DLUT sometimes visually improves even a screen that measures nearly perfect using basic characterization. :)