Author Topic: LUT Color Profiles  (Read 2968 times)

Just updated to 2.5 today and I've been looking into ways to help unify results from SP to UE4. Obviously there are differences with how the two generate and use IBL, but since Painter supports LUTs for better color correction/tonemapping, I'd like to bridge the gap a little more.

I understand that a majority of the LUTs provided are in log for the specified camera for future post-process, but none of them stand out to me as being of an ACES variety. Could I get some additional clarification on the provided LUTs and if I'm missing something for ACES? Thanks!

Edit: I've gone back to the changelog and a 3rd-party site lists ACES as an option, but Allegorithmic's doesn't, so I think that's where my confusion came from with expecting an ACES LUT.
Last Edit: June 22, 2017, 07:52:17 am
Lighting Artist @ Crystal Dynamics
Former Lighting Artist @ Obsidian Entertainment

The provided LUTs are just a sample but we will provide ACES LUTs in a future update.

I'm also interested in an ACEScg LUT being provided.

any update?

You wouldn't want an ACEScg LUT, because it would just look like linear, too high contrast etc. 

If you're in an ACES workflow, then you'd need to do the following (I've tried most of it and it seems to work ok):

*  Convert all your textures from Painter from linsrgb->acescg using oiiotool or Nuke
*  Create a Substance LUT for the OCIO / ACES view transform of your choice (eg: Rec709, DCI-P3, sRGB)

I (think) I was able to take one of the existing colorluts and apply the inverse color transform in Nuke to get the "raw" one, and then applied the view transform I wanted to it.  But I need to double check that actually did what I wanted it to. 

I'll double check my approach works, can provide details if it does

That's actually what I did but all within Substance Painter. I initially made a LUT (ACESFilm) from linear sRGB to sRGB passing through the RRT but the RRT always assumes ACEScg space so results turn out a bit darker. A better way is as you pointed to convert textures to ACEScg then pass it through a proper RRT lut (ACESFilm - ACEScg). You can find details here. I also made an automatic "PBR SmartFit" filter that works along the ACEScg filter (for PBR ACEScg textures).
Last Edit: February 15, 2019, 08:11:14 pm