iOS 14.5 & TvOS were available this morning and I updated both the Apple TV and my iPhone X to try out Apple’s Color Balance. Not straightforward with a projector since color balance is designed for monitors and TVs. A quick surf of the Internet showed how to do it. You have to cover Apples front camera with a muslin cloth of similar white tone to your screen and aim the front camera at the projector. Essentially, the iPhone camera sees the color on your cloth and not on the screen so the cloth must be the same white tone as your screen. Took me some time to find a handkerchief that was the same slightly off white tone as the screen.
Took just a few seconds for the calibration. Apple TV was set to 4K60 HDR and the WCG filter was on for the BenQ W2700. So its now confirmed that the calibration can be done on HDR/WCG. After the Color Balance was finished, the Apple TV shows a static picture with Color Balance On. You can switch it off to compare. For me, the brightness, contrast and saturation were much better with Color Balance On than with it disabled. So it works… at least for the static picture that the ATV displayed.
Its not possible to simply switch Color Balance off and on to compare in movie clips. Once you switch it off, the whole process has to be restarted from scratch. So A/B comparison is hard. If I switch out of HDR/WCG mode to 4K60 SDR on the ATV, color balance also becomes disabled. While it is reenabled, if I switch back the HDR/WCG, its clear that there is only one color balance memory and I either apply it to HDR/WCG or SDR (BT709). I’m quite happy with my SDR calibration anyway, so my main use would be for HDR/WCG.
As for Dolby Vision, if I enable DV for the ATV interface, Color Balance is no longer an option. Generally though, I have my interface in SDR and have color space matching turned on on the ATV. Hence, the system switches to DV only when I watch a movie that is actually encoded in DV. In my case, I am using Player-Led DV from the ATV and I can’t tell whether Color Balance is actually on during DV clips even after watching several clips from David Attenborough’s Life in Color on Netflix a few times both in HDR10 and DV. Overall though, the DV stream is better than the HDR10 stream. In the beginning of Episode 1, Attenborough is walking on a backlit beach and the DV clip looked a lot better to me than the HDR10. Human skin tones look similar so I’m going to stick to DV whenever its available.