(TL;DR: just a huge thanks from me too! For more, keep reading at your own risk 
Hi,
I just wanted to join the crowd of fans of this awesome project. I have been playing with it for the past 10 days, essentially since the moment it was announced. I am continuously amazed by how easy it is to get great results. Kudos @arctic!
So, I immediately started thinking about how to incorporate this into my workflow. The code is way too complex to just “borrow/steal” it, and it requires a level of knowledge of the whole film processing pipeline that I simply do not have (though the diagram above helps quite a lot in getting the big picture).
At first, I tried to see whether I could match the renderings with more conventional digital tools for tonemapping and colour grading. Well, yes, you can get close, but it’s quite a bit of work, and the closer you get, the more fragile the “standard digital” way becomes (meaning: you might get close for a particular picture, but getting something robust seems much harder).
Therefore, I started thinking of another way, and I now have something that I consider good enough for my purposes. Basically, I managed to extend ART’s support for 3dLUT plugins to allow it to use “externally computed 3dLUTs”, that can run arbitrary code to compute a LUT in CLF format, and then use it in the ART pipeline. After a bit of boilerplate (really, just a couple of hours of coding), I managed to get something working. I can now enjoy the awesomeness of @arctic’s work (*) inside ART – and this makes me smile
Here’s a little demo just to prove I’m not making things up:
(As you can see, it takes some time to (re)compute the LUT after changing settings, but (a) this is cached so reapplying the same settings is then fast, and (b) my laptop is really getting old now…)
(*) NOTE: this only works for the “tone mapping” part of AgX-emulsion; I had to turn off all the spatial processing (e.g. grain, halation, and other diffusion-based processes). This is not a big deal for me, since I was mostly interested in the tonemapping stuff, and ART has some (way less accurate and convincing, but still) other way of faking grain and halation. But definitely something to keep in mind.