Hello again!
Some more thoughts I have regarding the blues…
I had a look at last week’s meeting, thank you for briefly discussing my points! I think Kevin came with some good questions and tests of what happens with it in the DRT. How much of blue should appear close to/or max blue? How much of that should be considered “that’s just how it renders” or “it’s wrong it should look different”?
I find myself looping in two main thoughts about it …
- ACES 2.0 ‘brands’ itself as CAMDRT, which to me in simple terms means ACES 2.0 holds a color appearance model, which in turn should present an image as close as it can appearance-wise to how the captured data actually was when observed on the spot by a human within the defined display’s capabilities/limitations.
I think I can understand that within that subject there are a lot of subtleties, and different mechanisms can serve as being a part of color appearance. But to my mind, the most important one should be that any light emitting a certain amount of energy in any visible light wavelength, and any surface reflecting that light should have a certain falloff. If the DRT is unable to represent that falloff with just one color(range) (in SDR mostly), how much can we validate that the DRT is working as intended/desired?
- I don’t know how valid it is to view one output channel post DRT but when I look at v055 (even DCTL maths version) green channel, this awkwardly tight range of sudden saturated blue is very visible. When I look at other DRTs I have at my disposal, none of them show this issue. In the darker blue area with the piano some others do clip/fall to black but this is visually imperceptible to me in the RGB image.
Below are a bunch of DRTs I threw in to compare.
Top left = v055 (white border). The others: custom params AgX, JzDRT, IPP2, OpenDRT, DaVinciDRT
In the closeup you can really see that it’s also dark at the edges and bright within. I’m not a super technically skilled colorist but it feels wrong what happens here. Perhaps it can be analyzed and/or explained.
Last points about the other feedback I had regarding appearance of blue in the night scene, I can live with the idea that if the captured scene data/IDT put the information there more in cyan/green region, that’s how the DRT renders. This is very trivial and subtle to adress in grading if needed. I actually like the idea that you can discriminate such ranges while looking at the rendered image. Controls would be tighter but more 1:1 with where you are actually moving the colors to.
To conclude, to me personally I think overall the ACES2.0 CAMDRT is really almost there and looks very pleasing to work with in general. It’s just that last bit of blue that feels like a technical issue for which once adressed, you could say that the DRT is finished.
I would be sad if ACES 2.0 releases and I still have to say “this is ACES, but… you’ll need this to fix it”. 