Just to summarize, I’m a 3d CGI sup/artist in a french studio and I’ve been watching/learning ACES for about two years now.
I think I’m pretty much used to it and planning to “teach” it to my colleagues soon.
As I don’t want to spread false or approximate infos, could anyone help me confirm or correct what I’m about to tell about LMT, RRT and ODT ?
I saw here and there some infos about it, but it still feels blurry in my mind…
Let’s start with the RRT/ODT :
First I read that there’s a “primaries” conversion to AP-0 gamut (by the way is it just a primaries conversion, or a full colorspace conversion as data may come from ACEScg or ACEScc/cct ?)
Then, I’ve heard of a shaper curve. Kind of a “log” transfer curve applied to fit HDR datas into a 0-1 range. (is this step dependant on the ODT ? is the curve the same for SDR and HDR ODT ?)
Then, a S-shape curve is applied (by the way is it applied on all R,G,B channels equally ?)
Finally, the ODT remaps the primaries to the output/display colorspace (is a transfer curve still necessary at this point ? eg. for sRGB output, is the sRGB transfer curve applied too ?)
Second point is about LMT :
I’m not very familiar with this step as I don’t really understand where it takes place ? If i’m not wrong, it is some kind of LUT that you apply on ACES data to give a look before the RRT/ODT. Then how do we generate this LUT, in what software, to what format, and then how do we apply it ?
Feel free to correct any word that I misuse as I think terminology is the key when working with ACES…
Of course this is a kind of subject that may have been talked in other topics, but to be honnest, I really never found a clear, precise and reliable one about this. It’s always like fishing infos here and there, and at the end, there’s still missing puzzle pieces… ^^
Thank you in advance