macOS 11.6 P3D65/ST.2084 PQ (Dolby Vision) Calibration Workflow

[Jonathon Irons]

I am working on a show that is delivering for Dolby Vision specs, and I want to make sure that I’m doing my calibration correctly given the way that macOS handles color management. The target specs come in two categories:

1000-nit Peak White
P3 Color Space
D65 White Point
SMPTE ST.2084 “PQ” Transfer Curve
Full Range RGB 0-255

100-nit Peak White (“SDR Trim Pass”)
Rec.709 Color Space
D65 White Point
BT.1886 Transfer Curve
Full Range RGB 0-255

I am working with three types of monitors, which don’t need to visually match each other side-by-side:
– M1 2021 iMac 24″ (500 nits, 99% P3 Color Gamut Coverage, at least 10-bit panel, PFS Phosphor backlight)
– ASUS PB287Q 28″ (200 nits, 96% sRGB, 8-bit+FRC panel, White LED backlight)
– Canon DP-V2421 24″ (1000 nits, 99% P3, 10-bit panel, RGB LED backlight)

And using the i1 Display Pro Plus colorimeter (up to 2000nit measuring) with DisplayCAL.

I’ve tested a lot of different calibration settings trying to understand things, and this is what I settled on today that I felt confident about:

Profile 1: P3D65/PQ
1) Choose display & instrument, leave check boxes off, Output levels to Full range RGB, and Correction to the monitor type.
2) Turn on Interactive display adjustment, set Whitepoint to “Chromaticity coordinates” of 0.3127x, 0.3290y for the ASUS and Canon, “As measured” for the iMac, set White level to monitor’s peak luminance, set Black level and Tone curve to “As measured.”
3) Set Profile type to Single curve + matrix, enable Black point compensation, Testchart to Auto-optimized.
4) Hit Calibrate & profile. For the ASUS, set to Standard mode, adjust brightness and color gain to match white point and white level. For the Canon, set to DCI-P3/PQ EOTF/D65 mode, then adjust contrast and color gain to match target (using a very small measurement window to allow the panel to hit 1000 nits). For the M1 iMac, make sure “True Tone” and “Automatically adjust brightness” are turned off in System Preferences/Displays, switch to white level-only measurement in DisplayCAL, use github.com/nriley/brightness tool to match target.
5) Run the profiler, install the resulting ICC profile.
6) Return to Calibration tab, turn Interactive display adjustment off, leave Tone curve As measured.
7) Change Profile type to XYZ LUT, no Black point compensation, Testchart to 425 (personal preference), run the profiler again, say NO to changing to Single curve + matrix, say YES to including the current calibration curves.
8) Do not install the resulting ICC profile.
9) Open 3DLUT Maker. Set Source profile to “DCI-P3/SMPTE-431-2 D65 ST 2084 10000 cd/m2”, Tone curve to SMPTE 2084 (hard clip), Target peak luminance to monitor’s white level, Destination profile to the XYZ LUT created in step 7, turn off Apply calibration (vcgt), Gamut mapping mode to Inverse device-to-PCS, Rendering intent to Relative colorimetric, 3D LUT file format to .cube, Input/Output encoding to Full range RGB, and 3D LUT resolution to 65x65x65. Create the 3D LUT. Optionally create a second 3D LUT using SMPTE 2084 (roll-off) for Tone curve using the same Target peak luminance.

Profile 2: Rec.709/BT.1886
1-8) Same as before, but switch Canon to ITU-R BT.709/BT.1886 EOTF/D65 mode, and set all three monitors to 100cd/m2 white level.
9) Open 3DLUT Maker. Set Source profile to “Rec709 ITU-R BT.709”, Tone curve to Rec. 1886/Gamma 2.4/Absolute, the rest same as before.

For Resolve 17.3 (free version) viewing:
1) In Resolve Preferences/System/General, enable “10-bit precision in viewers” but DISABLE “Use Mac Display Color Profiles for Viewers”.
2) Go to Project Settings/Color Management and enable “Display HDR on viewers if available”. Set Color science to ACEScct, ACES version 1.2, No input transform, Output transform to P3-D65 ST2084 (1000 nits), leave the others at default. Copy the 3D LUT files created earlier to Resolve’s LUT Folder, then Update Lists and change the Video monitor lookup table to the P3D65/PQ LUT for the current output monitor, Save settings.
3) Restart Resolve to finalize changes.
4) Set imported clips to correct ACES Input transforms.
5) Make sure monitor settings for brightness and color gain are at the correct values for peak luminance and System Prefs/Displays/Color/Display profile is set to correct 1xCurve+MTX profile.
6) To switch to 100nit trim pass grading, adjust monitor settings and display profile, set Resolve’s ACES Output Device Transform to Rec.709, and the Video monitor lookup table to the Rec.709/BT.1886 3D LUT for the current output monitor.
————————————–

Can anyone confirm that my process is sound? I’ve been scouring the internet and these forums for every bit of info while I worked this out the last few weeks, so I hope I’ve at least got very close.

The only remaining issue I haven’t solved is that I have not successfully forced either the M1 iMac or a 2013 Mac Pro to output Full Range RGB 0-255 values + 10-bit. The M1 iMac is hooked up to an ASUS through USB-C->DisplayPort. The Mac Pro is hooked up to an ASUS through miniDP->DisplayPort and to the Canon through HDMI. According to the Canon manual, that monitor is capable of 3840×2160@60Hz, 4:2:0 YCbCr 10-bit, or 30Hz, 4:4:4 RGB 10-bit. But I’ve only managed to get 4:4:4 YCbCr 8-bit or 4:4:4 RGB 8-bit according to the Canon’s internal signal info. I learned that the 2013 Mac Pro’s HDMI port is 1.4, so I got a miniDP->HDMI2.0b adapter, but no luck. I also got an HD Fury Integral 4K to mess with the EDID, but that hasn’t helped either.

Thank you everyone in advance!

-Jonathon Irons

• This topic was modified 4 years, 7 months ago by Jonathon Irons.

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[Jonathon Irons]

It turns out there was a flaw in my process at least regarding the Canon DP-V2421 – it seems like putting the monitor into its DCI-P3 Color Space and PQ EOTF was the wrong move to make prior to calibration/profiling, and resulted in lots of strange color glitches, esp. in Resolve. I chose a new user preset on the Canon and turned off everything I could including the color space and EOTF settings, leaving it at native. Unfortunately this reduces the peak white level of the monitor to ~700nits instead of 1000+, which seems to be dependent on the monitor’s EOTF setting. But, profiling with the native settings (aside from tuning the color balance to D65 and setting a white level of 600nits) took away the glitches. I’m still confused about when the monitor’s PQ setting should be enabled, but I will have a Blackmagic DeckLink Mini Monitor 4K card shortly and will hopefully discover more when I’m able to send a proper HDR signal out of Resolve.

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