ART and OpenColorIO

Is there a txt file or some instructions floating around for building on Windows. I tried a couple of times using the suggested steps on the rawpedia link and subst the art repo for RT but it fails. I feel like I was able to build it a few months ago a couple of times but since then I get some errors…

I can be a bit more specific later…dashing off to work but if they are written down or you have a cheat sheet that you could share I would appreciate it…


I should be able to write a guide on the basis of rawpedia/windows (as I maintained it for a few years)
it’s WIP :thinking:
A first “preliminary and incomplete” draft here W10 build.odt –

Your very kind. Thanks… I updated my build configuration a few times in the last month’s so it could be the issue or my syntax could be a bit off… thanks for taking the time to respond and help

I get this issue…I thought there was a typo but seem like not and answering yes or no still seems to fail… :slight_smile:

I dont know why in rawpedia the mingw-64-X86_64-pkg-config is listed in the packages to install.
The package to install instead is mingw-64-X86_64-pkgconf which is compatible and more modern.
Corrected in my draft.

Thanks I did get further along and even through to install but the exe fail throwing a few errors… I will try maybe from scratch again as I am sure there is just something small going on in there…thanks again for all your feedback…would be just all misguided trial and error without it…

Sorry if I pick this up again. I really don’t like self-advertising, but I have a feeling that I failed to communicate the significance of this new feature. Despite the name, CLF LUTs are not simply look-up tables, but can encode a sequence of different pixel-level operations, including matrix multiplications, ASC CDL operations, and per-channel transfer functions. What this means is that they are well suited to be applied in a scene-referred workflow, e.g. to implement “look transforms” or also “output transforms” (i.e. tone mapping operations from scene to display/output). For example, now it is possible to apply ACES output transforms directly in ART, or even color grade pictures using look+output LUTs developed for high-end professional cinema cameras such as ARRI and RED.

The only thing needed is to convert such LUTs to CLF and combine them with the appropriate color space conversions to/from ACES 2065-1 (which is the color space used by ART to apply CLF LUTs), all of which can be done with OCIO tools such as ociomakeclf and a bit of scripting.

As an example, I’m attaching one of the current candidate output transforms for ACESv2, converted to CLF. To use it, just uncompress it (or change the extension to .clfz), put it in the directory of your film simulations, and then apply it with the tone curve turned off, like this:

ACES ODT Candidate A - SDR.clf.gz (1.7 MB)


This is indeed really powerful stuff Alberto! I am not an avid LUT user myself, nor can I find other CLF LUT samples online, but a lot can be done with them it seems!

Perhaps @Andy_Astbury1 would be interested to take a look at the creative possibilities this generates?

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The nice thing about this is that essentially any lut out there can be easily converted to clf with tools shipped with ocio and (if needed) a couple of color space transforms that can be implemented in a few lines of python.

Indeed. My original motivation was that I wanted to be able to use the output transforms that have been developed by the movie industry (such as the ARRI, RED and ACES ones that I mentioned above), as they are high quality, robust, and come in different flavours for different output displays (standard SDR screens, wide gamut, and fancy HDR ones), providing a consistent look throughout different output devices, which is the main (if not the whole) point of scene-referred editing…
But there are other applications as well. For example, the rgb color grading tool in art operates in linear space, but if you would like to grade in a log space, now you can: just apply a lin-to-log lut at the beginning and a log-to-lin at the end, and your grading layers in the middle.

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Next up: ART can now color grade video! :wink:

I know you are joking, but I have been playing with the idea of generating a CLF LUT out of an .arp sidecar. This would actually allow to grade video with ART – well, sort of :slight_smile: – using tools that support OCIO (such as Natron and – I believe – Nuke or even Resolve). I’m not really sure if I’ll do it, because I don’t do videos so this would be a purely academic exercise, but in principle it’s possible…


FYI, the patched opencolorio 2.1.2-3 package including the .pc file should be hitting the MSYS2 repos soon, and should hopefully work OOTB.


I’ve added some docs on how to generate CLF LUTs to be used in ART: agriggio / ART / wiki / Luts — Bitbucket


All this is very intersting! Thanks alberto.

Hi @agriggio
Thank you very much for this new feature!
I am very interested in luts in general as when they are well used, they are the easiest way for me to get a consistent look across a bunch of images.
I will take some time to experiment.

Hi @agriggio

I think if you add the function to manipulate ociomakeclf.exe from ART menu, it is useful for many users. Because I think it is difficult for non-developer users to install OCIO tools except on Mac OS, and without OCIO tools, especially ociomakeclf.exe, many users cannot enjoy this new feature of ART.
So, if you can distribute ART binary files including OCIO tools and add proposed function, it is helpful for ART users.
Thank you for your attention.

And thanks for the comments!

I’ll see if I can include the needed OCIO tools in the binary distributions, or maybe if I can add the equivalent functionality to ART-cli. I have no plans to add a gui for this though, I think it’s difficult to come up with something reasonable and the benefit would be very limited.

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I’ve added links to pre-built binaries for ociomakeclf to the wiki page (scroll to the bottom): agriggio / ART / wiki / Luts — Bitbucket

Thank you for your quick response!

Resurrecting this fairly old thread, I could at last take a look at this new feature.
I read Alberto’s wiki page on the subject, and I converted ARRI and RED cube look LUTs to CLF LUTs.
Applying these LUTs form the Color/Tone correction and Film simulation modules works great, and I get pleasing looking images. So, thank you again @agriggio!

Now, I confess that I don’t understand a lot about the different transforms that are run under the hood. So here’s my question: is it correct to use the ARRI and RED CLF LUTs as they are, on a regular (SDR) monitor? I’m asking because I saw that the ACES LUT you provided above ( ACES ODT Candidate A - SDR.clf.gz) has SDR specified at the end of its name. If I’m not mistaken, the ARRI and RED cube LUTs are log-to-log, but I’m guessing that it is okay?

If you followed the procedure in the wiki, the luts you get are meant to be used in scene linear space. So you can apply them in colour/tone correction, i.e. before the tone curve. If you use them in film simulation, you might still get a pleasing result, but such result could be different from the intended one. On the other hand, if you like it, who cares? :slight_smile: