Hello guys,
I don’t know if after the TAC meeting of today (17th of November 2021), the road of Color Appearance Models will be pursued. But I wanted to share a couple of things.
I do remember someone saying at one of our previous meeting (Thomas maybe ?) that we should cherry pick our color appearance phenomena. Like maybe pick one effect over the others. And I was wondering if you had checked by any chance tone-mapping solutions that are related to the Helmholtz–Kohlrausch Effect.
It took me a while to wrap this up into my head. But here is the logic behind it. With tone mapping, we are trying to handle gray scale information in a predictable way (quote of Rory Gordon). This gray scale information can be called luminance or brightness.
All the images I have provided over the past months, when they look weird or wrong, it is because we have lost this sense of tonality. Like a broad range of values have collapsed into one and are clipped onto the border of the gamut display volume, right ?
And so, coincidence or not, the Helmholtz–Kohlrausch Effect belongs to the… Brightness appareance type… And I was wondering if you had ever googled “Helmholtz–Kohlrausch Tone Mapping”.
There has been some interesting research about this phenomena that might be worth exploring and may be like reducing our development cycle, since we have until end of next January to come with some sort of plan if I understood correctly.
And if I’m correct, this wraps up with the whole stimulus/sensation topic.
You have a three “equal” stimulus that lead to three different “sensations”. And vice-versa. It is very well explained in this tweet : stimulus maintains a non uniform relationship to sensation.
I must thank @Troy_James_Sobotka to explain all this stuff. I hope I am not butchering the terminology here. And I will stop here since I feel like I am dealing with stuff that I barely understand… 
Chris