Hey guys! Really appreciate your patience and responses, as always
So, first, let me apologize – “an ODT that bypasses the RRT” makes pretty much zero sense. ODTs are, by definition, RRT-refferred; and “bypassing the RRT via an ODT” would be applying a meaninglessly dumb operation on the wrong side of the equation. By “ODT that bypasses the RRT”, I’m realizing I mean an ODT-referred LMT that serves to “neutralize ACES tone mapping” so… roughly, AP0-to-display + EOTF + invODT + invRRT I suppose.
Jim, your points are well taken, and I’m fully picking up what you’re putting down – for our matte painting department, we’ve tried both approaches you suggest – working on Log integer data under an appropriate concatenation of transforms, as well as working directly on top of display-referred plates with invertible transforms… the latter seeming especially dirty to me, but it’s better than the alternative (having to work on top of power-windowed, grade-baked-in, plates… in 2017…).
I was speaking in particular about painting diffuse textures for CG, however, which has pretty different restrictions and workflow requirements; in particular, linearized diffuse texture RGB values must not surpass 1.0; else, physically based renderers are inclined to treat the textures as emissive. Painting linearly but viewing under the RRT+ODT would roll off acescg values greater than 1.0 (and presumably appear darker compared to a straight acescg --> bt.1886 gamut and conversion transform). But more to the point, these are normalized, linear color maps intended to be perceived as such by the renderer – plus, if texture artists are pulling in an sRGB image, they have a certain expectation that’s more or less thwarted when when they discover that sRGB --> acescg --> aces --> RRT+ODT (sRGB) is not the same thing as sRGB --> acescg --> sRGB. And neither are the same as evaluating under what the actual shot or show lut(s) look like.
I guess I’m not certain if neutralizing the RRT+ODT tonemap via LMT is “truthier” than leaving it in. If all our shows were ACES shows, I’d feel pretty good about using the RRT+ODT in texturing; but since we have about as much ACES work as we have non-ACES work, it’s difficult for me to determine the most appropriate way of viewing to preserve “job independence” in our assets. As Alex suggests, there are a lot of nuances… lot of ins, lot of outs, lot of whathaveyous.
Sorry guys, I’ve derailed this thread a whole lot. Please feel free to move / delete / prune whatever you’d like. I think it’s more important that you guys get the feedback requested, rather than hearing me harp on these edge cases that are probably suited for other threads…