Originally Posted by thirdkind
Just wanted to follow up on this recommendation. Thank you! I performed a calibration last night using this white point and it's already a great match to what I see on my other displays, even without manual tweaks. I plan to do a side-by-side comparison sometime this weekend, but I can't imagine I'll need to touch the gains much at all to get it spot on.
You can see below why the initial custom co-ordinate you used didn't worked well and the custom co-ordinate I suggested you to use has better visual match, lets see the reason below....
Color Matching Functions & Metamerism
The CIE 1931 color matching functions (CMFs) are the basis of all colorimetric measurement systems.
Earlier studies intended to correct historical imperfections in the original data used as the basis of the CIE 1931 CMFs, but like the CIE 1964 Supplementary Standard Observer, have never found widespread favor, because they result in different numbers across the whole colorspace.
Color scientists attempted to define a more accurate CMF but they resulted in a set of CMFs which can solve the metamerism issue for discrete populations of individuals but this would probably not be practical in an operational environment.
These inaccuracies were not a problem when all display devices were CRTs with color reproduction based on very similar phosphors.
With the introduction of LCD displays with LED backlights, and now OLED displays, it has become apparent that these errors result in displays where the white points match when measured may look different, and when matched visually may measure differently.
For Matching Displays that use Different Illumination Technologies, the Perceptual White Point Matching method can be used.
Using a custom coordinate White Point, it may be a practical compromise such that the display may meet both the requirements of written standards, and enable the visual match that is so important in the television production environment.
LG Electronics with Dolby Laboratories have published an article during SID's Display Week 2018, its available inside to SID Symposium Digest of Technical Papers - Volume 49, Issue 1 (May 2018) issue.
For that study, 'Correcting Metameric Failure of Wide Color Gamut Displays', using 13 reliable observers they performed a visual color matching method trying to match a Reference Grade-1 CRT with the LG OLED and they found that to perceptual match the Reference White of CRT, a custom White Point with x: 0.308 y: 0.313 coordinates has to be used for the LG OLED.
Also LG has worked closely with Technicolor to incorporate Technicolor's in-house D65 perceptual match White Point target, by adding a custom target white point with co-ordinates of x: 0.300 y: 0.327.
But these coordinates are not really working, because Technicolor tried to match a Xenon DCI Cinema Projector as reference (with DCI primaries and D65 White Point), so these coordinates are only helpful for those which are working in post-production and use LG OLED's as client view monitors, for the commercial cinema release of the movie.
For home video release of a movie, a projector as reference is never being used, only with monitors its been performed the mastering of SDR home release of the movies, so there no point for anyone to use a Technicolor custom White Point (for home viewing).
Each colorspace (REC.709 for home release or DCI-P3 for commercial cinema release) while they use exact the same xy coordinates to create the D65 White Point, each colorspace is using different mixture of primary colors luminance to archive that, while both have 6504K color temperature.
When you use the RGB Balance Chart of a calibration software and see the three (R/G/B) Channels Bars at exact 100% = 0 dE; doesn't mean that it has been used equal percentage of luminance per each color channel.
The calibration software it's doing the normalizing the luminance ratio per primary color internally according to the selected colorspace target options to provide to the user interface a more calibration friendly chart.
REC.709 Colorspace D65 White Point (x: 0.3127 y: 0.329, 6504K) is using Red 21.27%, Green 71.52% and Blue 7.22% luminance per each color channel.
DCI-P3 Colorspace D65 White Point (x: 0.3127 y: 0.329, 6504K) is using Red 22.9%, Green 69.17% and Blue 7.93% luminance per each color channel.
REC.2020 Colorspace D65 White Point (x: 0.3127 y: 0.329, 6504K) is using 26.27%, Green 67.80% and Blue 5.93% luminance per each color channel.