Read on Twitter
Apple tvOS 14.5 is out, which means their new Color Balance setting is there to help correct colors on your TV. To find out if this works, I tested with an LG C1 OLED and used Calman, and fed test patterns over Airplay, this is in 4K SDR.
I started out using my fully calibrated (3D LUT) Expert mode. This made sure my test patterns were working correctly since I wasn't using a normal test pattern generator. As you can see, error levels were very low here and the comparator looks great.
So I ran Color Balance on this mode and as you'd expect there is very little change. Slight increased in error levels, as my meter is more sensitive than an iPhone, but overall it's exactly the same.
For the next test, I set the TV back to Standard mode and made zero adjustments. As you can imagine, this was very inaccurate out of the box, and you shouldn't use this mode, but here are the original measurements.
So I ran Color Balance again here and it didn't really change much at all. The 100% white bar at the top is better, but red is a bit worse, and overall errors are still extremely high. This isn't calibrated by any stretch.
If you look at the CIE diagram, post-calibration the Cyan, Magenta, and White points are closer to their targets, but the gamut coverage only shifted from 133.1% to 133%, or within the margin of reading error. Again, no major changes.
I haven't tested HDR, and maybe that can help with the EOTF, but my overall takeaway is that this feature can make slight changes, but it's not a calibration, and you selecting your TVs most accurate mode will make 100x more difference than doing this ever will.
Also, I've seen people mention that this improves shadow detail for them. None of the patterns it measured went below 50% I don't think, so it shouldn't impact shadow details at all, that's a placebo effect.
