OK, so given my report of the LLDV gamma curve, (probably following PQ - approximation?) is too dark on my my x990, I have been thinking about what options might available on the x990.
I tried looking at the black floor and my master contrast setting, as a way to restore shadow detail, and LLDV reference black is still the same at +2 brightness on my x990. so that is out.
Next I have tried using the st2084 WHITE Dark Level adjustment and its max of +7 is not enough. So I am tinking with going further by boosting Dark Level for RED, BLUE and GREEN. This in addition to boosting the WHITE, is bringing out more shadow detail on my brightness clipping pattern. I have not tried this new approach with content yet, but will try it with both a DV UHD title and some HDR10 UHD titles. And as I said in a previous post, this is still tweaking to the eye, to see if there is merit to going further into measuring and plotting the data.
Further, I downloaded Ryan's free sample DV test patterns, and while the HHDR10 color bar patterns I have look pretty good being forced to LLDV, the DV color bar pattern is under saturated. I find this interesting, because the level of under saturation in the DV test pattern, is not consistent with the color saturation of the few DV titles I have checked, and given the DV test pattern, it should be more apparent on the DV movie content.
Lastly, in an effort to get my old Dell Insperion awoken from the dead, I was able to get not only the vertex GUI running on it, I was also able to install JVC Auto Calibration software on it. So the next step would be for me to dive into custom curves. Not to get beyond the peak white lumens I can reach with the onboard st2084 controls, but to see about the shape of the gamma curve to work on shadow detail and up thru peak white.
Z has mentioned his working on a custom curve, and I am curious if he has checked to see how that curve tracks for HDR10 vs LLDV, and is LLDV is showing more of a gamma bump, like a PQ curve would?
Lastly... regarding color profile, I have a spyder 5 I can use with JVC AutoCal, but my old copy of CalMan 4.64 is not booting up. An older version of 3.5 is booting, but that is way old.
So, even if I could reinstall CalMan 4.64, the Spyder 5 is not likely on it's sensor list. So rather than invest in a newer CalMan license, I'll see about one of the newer free alternatives. (HCFR ?).
In any case, I'm much further down the rabbit hole than I have originally expected, and it is a wee bit exhilarating.