I'd like to create a 3D LUT for an OLED panel (Flanders/LG WOLED EP/BP series) that can replicate color from an Apple Display P3 device (XDR display, Studio Display, iPhone/iPad). Many clients review work this way, and it would be a helpful option to see these colors on a mastering display. I've gone into an existing .bpd preset (sRGB) and modified the primaries to reflect the Display P3 primaries (based on https://en.wikipedia.org/wiki/DCI-P3), and kept gamma at 2.2. The latter as I understand it, should also match sRGB ("Pure Power"?), but it appears one can only specify 2.2.

The result (from a 17^3 raw profile on a 32BP95-E probe matched to CR300) is a LUT for which primaries more closely resemble AdobeRGB than they do P3/2.2: the reds are more pure red, and less saturated/skewing orange as they appear in Display P3. Have I gone about this correctly, and/or is there a better way to match? I could profile my MBP XDR screen, but I don't have offsets/EDR or a good spectro, so hoping for a better route.

Andrew Huebscher
Los Angeles, CA

From the website info on the 'Grading Calibration?' page.

"Apple have what they call displayP3 colour space, which incorrectly combines the P3 gamut with the encoding sRGB compound gamma - not even the correct display defined sRGB gamma, which is a power law 2.2 gamma."

The gamut is P3, but the EOTF is using the incorrect Encoding sRGB values.

If your display has a different gamut to P3 D65 it is incorrect in some way.

Steve

Is this to say they have incorrectly stated how they arrive at that profile? Or is it that there is an inherent conflict in combining that gamut with EOTF?


Isn't my display's gamut overruled by CS profiling in raw and subsequent loading a LUT?

Apple P3 just uses an incorrect EOTF.
It's that simple.

So, Apple Display P3 is standard P3 Gamut, with the sRGB Encoding EOTF.

Steve

To be a bit more specific:


The link to Wikipedia doesn't seem to work, so I have no idea what values you have used - But the correct values are within ColourSpace for P3 D65.
And I do not understand the comment "kept gamma at 2.2. The latter as I understand it, should also match sRGB ("Pure Power"?), but it appears one can only specify 2.2." What do you mean exactly?
But be aware of the above info on Apple using the wrong Encoding EOTF.


The native response from any wide gamut monitor will nearly always be a gamut that is not any standard colour space, and will be close to a 2.2 power law - all screens natively are a 2.2 power law EOTF - that is how they are manufactured.

Any further help?

Steve

Apologies - I copied the link wrong. This is the correct page: https://en.wikipedia.org/wiki/DCI-P3
I've verified the primaries shown there are a match to CS's P3 data.


What number would I need to specify for gamma in a CS preset that will mirror's Apple Display P3?


Is a "2.2 power law EOTF" the same as "2.2"?

As Apple use an incorrect compound Encoding EOTF, you would have to use the Parametric EOTF capability of ColourSpace to mimic that.

And yes, '2.2 power law EOTF' means '2.2'.
The alternative is the (incorrect) compound Encoding EOTF Apple uses.
(Or a PQ or HLG, or BT1886 with lifted black EOTF...)

Steve

Thank you, Steve. This clears the gamma question up.

I'm still unclear about why I'm seeing different reds between the units (ASD vs. LG BP95). My LG is out for service, so I'll have to wait to re-profile each to understand which is showing an incorrect red for P3 (my money is on the Apple).

Can you recommend a spectral file to use with an i1D3 when profiling the Apple Studio Display... GB-LED?

One monitor is therefore not calibrated correctly...

But, remember Apple has ColorSync always active, so messes with any images sent to connected displays.
That obviously includes TPGs.

And no, unfortunately I have no knowledge as to what Correlation File would be close to the Apple monitor.

Steve