Either film simulation (which is what I would use for an ODT/DRT lut like this one) or colour/tone correction.
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Based on this description, looking at the CLF file and a brief test, it seems to work. 
I haven’t yet setup the original config in Blender so didn’t do an exact conversion yet but qualitatively it matches what I’ve seen in my own experiments and some done by others.
Image from GitHub - sobotka/Testing_Imagery: Colourimetric Test Imagery, converted first from EXR to 32-bit floating point TIFF in darktable.
Neutral profile as a starting point (so that no tone-mapping was applied). Just loaded the LUT and this was the result. It is as expected. Well done 
Should be something quite interesting to experiment with for the folks here.
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Thanks for checking!
Fwiw, qualitatively the output is a bit too flat and desaturated for my taste, but you can probably fix that with a bit of “look” tweaks.
I prefer the current ACESnext candidate A out of the box, or even better the RED “medium contrast, medium rolloff” one, as it is closer to a finished image. But these are just personal preferences…
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The ”AgX Base” look is meant to be that way. Eary has been providing updated AgX configs here as the experimentation progresses: AgX/config.ocio at main · EaryChow/AgX · GitHub
There are several creative looks but also the ”AgX Chroma Laden” look which adds a saturation increase on top of the AgX Base look. That should be more like a ”finished image” type of starting point. But yes, personal preferences indeed.
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Great, thanks! I’ll see if I can convert those to clf as well. I skimmed through the thread linked above but I didn’t have the energy to read all the 900+ posts in it…
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Yeah, no need. Eary’s most recent config contains also a spherical compression (done before the image formation) but that is still the topic of ongoing experimentation and it’s not yet settled on.
Here’s the “chroma laden” version of AgX as a CLF. This time I used a different approach to create the LUT, leveraging ociobakelut plus some log shaper at the beginning to ensure that it is applicable to a suitably large dynamic range. It looks ok to me (in the sense that the contrast is similar to AgX but it’s more colourful), but independent checking would be good.
You can use it in ART either by uncompressing it, or by changing the extension to .clfz.
HTH
AgX_Chroma_Laden.clf.gz (1.3 MB)
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Hi, I revisited the blenderartists thread and saw a lot of activity there. So, here’s an updated AgX for ART based on the latest version by Eary_Chow. (To use it, either uncompress it or change the extension to .clfz)
AgX - EaryChow.clf.gz (1.4 MB)
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For those interested, there’s now an open pull request to replace Filmic (as in Blender’s current picture formation method, not to be confused with darktable’s filmic) with AgX in Blender.
Thanks for the info! If somebody is interested, I can easily generate the LUTs that can be used in ART.
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I’m interested!
@flannelhead do you know where I can find more info about how the guard rail works? I only see a LUT in the repository, but I’d be interested in the details of the algorithm. Thanks in advance!
Maybe this could help.
A brief description
The code
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Yes, I would’ve also posted these.
As I have followed the thread quite closely and took part in the guard rail experimentation, I can probably answer at least some questions if such arise from reading the links @agriggio
Awesome, thanks to both! I will read the material and get back with questions. Basically I’m trying to understand whether the guard rail can support HDR screens (say 1000 nits). I quite like how it handles the “path to white”, but the AgX config seems to be limited to SDR as far as I understood, which is a pity. (If I’m wrong, even better
In this post last year, you release another LUT with the same name, but it was much lighter (<19 kB) than this one, and of course the result is different.
Can you elaborate on the differences and use cases for both?
This is for the latest version, a lot has changed in the agx formula in the meantime. I didn’t follow the whole development but I think the last one is supposed to supersede the previous…
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The more recent version includes the guard rail transform which is AFAIU implemented as a 3D LUT, so that should make for the most of the bulk in the file.
The guard rail ensures the chromaticities are preserved when outputting to a narrower gamut footprint.
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There’s also the fact that I used a different method to build the LUT this time: instead of manually translating all the steps into equivalent clf operations, I used ociobakelut to do the heavy lifting, plus matrix operations and power and log encodings to convert from/to ACES2065-1. That’s much easier to do but the price to pay is that the bulk of the ops are encoded in a big 3d LUT, which in principle causes some loss of precision (though I didn’t notice any visible degradation so far)
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