Black not visible down to reference black

[((( atom )))]

Hi,is there any option in displaycal to raise the black level when making 3DLUTs? I am generating LUTs for Rec709 and DCI-P3 color space for usage with MadVR. I tell MadVR to use the Rec709 LUT for just that and the DCI-P3 as monitor calibration for usage with HDR-SDR conversion.

I get brilliant results exept for the blacks: Without the LUT I can distinguish black levels down to reference black very clearly with the LUT black vanishes a little bit above that.

Levels are correctly set throughout (FULL on the PC, and TV-levels in MadVR and on the projector).

Black point compensation sounds good but gives me a warning not to use it with 3DLUTs.
Black point correction also sounds promising but seems to help with colored blacks only (correct?).

Is there any other option i am missing maybe?

[((( atom )))]

After some reading I might be able to answer myself.

Using the LUT I noticed a slight reddish coloration around near black, so it seems the “Black point correction” is trying to sustain the chosen hue by adding some color which lightens the blacks.
Without the LUT the blacks are slightly blue-ish so that makes perfect sense.

I will try to adjust the RGB offsets to give more neutral blacks and turn off BPC. I had actually adjusted the offsets using HCFR but maybe that didn’t work out so well.

[((( atom )))]

That did the trick! – Adjusted RGB offsets to loose any tint and re-measured. Using the LUT I can now spot black down to almost reference black and visually the LUT now beats uncalibrated in every scene, bright or dark.

Again a slight improvement over my last calibration.

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