If you have access to Nuke, you could check the metadata the render engine wrote into the exr headers for more insight. The left img is stock Maya/Arnold color management, the right is ACEScg with OCIO color management.
I always presume that “lazy cgi linear” is 709/Linear but I am also lazy and hate trying to have the gamut conversation with my 100th CG dude.
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lets say 3D loaded in a linear/alexaWideGamut liveAction backplate and they use a renderer that doesnt support a full
aces workflow, what will
happen?
They will be either
-
looking at some kind of tonemapped view usually some renderer internal tonemapper, which usually leads to very desaturated colors as it expectes linear/sRGB source, and a “contrast” or “look” you cant match in flame.
-
Using a " viewing LUT in their viewer, usually thats some linear/alexaWidegamut to rec709 LUT, now thats nice because you could match the look, buuut → now they are transforming eveything from their texture authoring space to rec709 in a wrong way, so they are probably using color correction nodes in their shaders to compensate and thus matching their CG to the alexaWideGamut backplate.
and now from that point on you have to ask youself, is it really linear/sRGB or should you consider it as linear/AlexaWideGamut? or even something else? Where and how where the textures made…? its not simple!
And Now a wild nuke comper appears in the middle of it…
Nuke does not have a concept of gamuts by default, it also does not tonemap stuff, it only applies a simple linear->sRGB curve thats clips off stuff above 1. but you could load viewer luts and other stuff of course… you just never know ;-).
Not having a concept of gamuts means it just ignores them so in nuke it is just “linear” or “LogCv3”, you can mix those together as you want (grassmans law of color mixing) but you really shouldnt.
Its called colorpipeline for a reason, everytime information is lacking there is 1 VFX supe that doesnt know how to handle color, the info is there, but once you get renders as a flame artist its usually too late, this stuff needs to be handled first and and not last in a project.
in complex situations I usally take a piece of paper or a nuke comp and backtrace the complete color pipeline, who has seen what with what transforms? What is the expected result ? etc.
I urge you all to open up vray or arnold or redshift/ substance Painter to have a look at how limited things are , plates need to be properly prepped before CG gets it, thats where aces and OCIO is very strong, just from a production perspective you should have 1 entitiy be responsible to conform and to ingest plates correctly, should this be the flame person? Possibly yes.
The political part is hard, ive personally gotten most my regular clients to accept they need to involve me into all their color choices as far as having a phone call with the DP and DIT on set before they even shoot anything. They start appreciating it though as they know there wont be any problems downstream and it safes a bunch of time getting it right from the get go and not ending up with random exrs and prores files from unknown origin.
I am just so lazy and cant be bothered with manually grading everything to fit if it can be solved beforehand, it will
look better and take less time.
Hey and if you ever need a color supervisor on your project, you know where to find me (shameless Plug)
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