Preserving Logos and Graphics in ACES

[nick (Nick Shaw)]

@soulcage

if you do the inverse transform from ODT srgb to ACEScg you end up with extraorbitant raw color values, like 1.0 became 16.0 + the alphas are screwd up and your graphics become a light source in the cg-renderer…

You need to think of this in terms of how the logo would look if you displayed it on the screen of an actual monitor and filmed it with a camera. Whites in the logo would not be at peak white in a properly exposed image of the monitor (or there would be no room above that for speculars). In order to make the logo white hit peak white in a filmed image you would have to make the monitor so bright that it would be a light source, with the resulting “eating up” of dark text on the white background. That is what you are emulating if you feed peak white into an inverse ODT. A logo superimposed on a TV which hits peak white is not a photo-real image It is graphics, and needs to be handled as such.

[soulcage (Wilhelm)]

sure, if i would print out the logo from a file and then make a photo of it, i will never see the pure 1.0 value in it…

so but if my cg-tv looks super-photorealistic in aces (ODT rec709 lets say) but the clients logo on it or in reflections, etc. greyish, washed out, then i have a problem, because the client says “wow, the tv looks great, but my logo is strange”, then i have to swatch colorspaces (back to “normal” srgb) and do all again…(or seperate colorspaces)

so this would be a situation, where a “full” aces workflow would fail, isnt it?

[soulcage (Wilhelm)]

found this and its very informativ…
he discuss also the workflow how to preserve srgb textures with a inverse ODT workflow and the downsides of it…
thank you chris for putting this together.

Chapter 1.5: Academy Color Encoding System (ACES) - Chris Brejon

[Devon-Stanczyk]

Paul, I’ve had issues with this too!

Check your “resize filter” in the inspector panel. It’s under “retime and scaling” on the edit page in Davinci. I think by default, it is set to “sharper.” Changing to “smoother” should help!

[marco.sgorbati]

yes, it’s a resolve scaling algorythm issue when set aces science. the alpha goes crazy.
I usually fix it by changing the default “sharper” / “smoother” algorythm to the old “bicubic” or “bilinear” (see project settings or clip inspector in timeline). please note that scaling algorythm are often strictly connected with gpu type. this trick works well with amd fire pro d700.