There will be documentation as there is for all items and for sure the release blog post will have an entry. Technically it has just been merged so it is in testing. You can fairly rapidly scroll the 700 post thread and see where the image clusters and descriptions are…Filmic has been a very difficult module to get people to grasp and it has evolved and matured. I suspect that there will be some progression in the same way with Sigmoid but its simple and not trying to do too many things so I think it will be a much easier sell… I think in the link I provided above there are selected links provided to target most questions so if its not enough to learn it via self discovery there are definitely already some pointers to some basic information…
Great. Thanks
It really is all summarized pretty nicely here just incase you didn’t peek at it…
I did…
There curves tool that runs in a browser is really cool…you can compare filmic with sigmoid. Adjust the parameters and even compare to blender and other curve models…
At the very least it is a quick visual answer to Terry and and Tony wrt what do the parameters do… from a tone perspective…
https://jandren-tone-curve-explorer-streamlit-app-xca32q.streamlit.app/
The 12642 PR is a pretty good start …just needs some between the lines and some formatting to fit into the DT manual format…
Well volunteered
Both Filmic and Sigmoid are tone-mappers. Their job is to map the linear, scene-referred data to non-linear, display-referred data that your monitor (or print medium) can display correctly. They just do it in slightly different ways, providing different trade-offs.
Since it makes no sense to tone-map twice, only one tone-mapping module should ever be active.
If you don’t understand the scene-referred workflow and the role tone-mappers such as Filmic and Sigmoid play, I highly recommend the following:
Thanks. Useful. I “understand” filmic
Actually, the job of mapping tone to the rendition medium is the job of the color profile specific to the medium. Filmic, Sigmoid, and other user-futzed tone curves are an intermediary between linear and input to the rendition transform. If one is not using calibrated display profiles, these tools are probably filling the gap, but one has to be wary of exporting to JPEG and then wondering why the tone looks different…
See this post, where Jakob describes his recommended workflow (he’s answering several questions, so you’ll have to scroll down a bit):
Yes, I will supply the documentation asap! And I will do my best to explain the module in a more approachable summarized manner than the monster thread.
The short answer is that it should essentially be the same as filmic, but faster to work with.
Thanks everyone for quickly filling in with answers 
Yup, specifically compressing the dynamic range of the image into something that “plays nice” with a limited-capability display.
If you have an HDR-capable display, you can actually get really good results with no tonemapping whatsoever. For example, convert scene-linear data directly to HLG and feed to an HLG television with no tonemapping - works amazingly well. (For the time being, the only consistent way to do this is to encode an H.265 video with Rec. 2020 gamut and HLG transfer function, and make sure to set the ATC SEI metadata properly. Some people claim that HLG requires no metadata, but that’s a lie - if you don’t have the ATC SEI metadata it’ll be treated as Rec709 and look “meh” because HLG’s backwards-compatibility mechanism is actually a kinda poor tone curve with no “foot”.
But for 99% of stills content delivery, you need a good tonemapper. Honestly for the few cases I’ve seen sigmoid not perform great, you need a local and not global tonemapper. dt’s local contrast is one option, using enfuse on multiple images exported with different sigmoid settings would be another.
The funny thing about it is that the gamma curve that is part of display/export profiles was a CRT-specific thing; I’ve been told raw LCDs do not manifest this characteristic. So, the display manufacturers build in the gamma TRC for compatibility, and we have to mung our linear captures to conform, still… 
Thanks, Troy… 
I’ll have to go back and read what we have for tone-mapping and filmic. To me it makes sense to try and integrate sigmoid from the point of how the current tone mapping options are currently explained ie around why we use filmic and now saying why we could also use sigmoid as an option. This will cover both in a big picture sense and then the collective language about how to describe and present those options and the relative differences,merits etc would have to be ironed out. Then a module specific description of the sliders etc would need to be provided for that section of the module…
It’s been around for months and months . But it raises a discussion where some people thought it should not be included, or it base functions merged into filmic as a separate filmic mode.
Without going into details , that discussion is no more so it go finally approved to be included. So its now in the main DT source code and will be one of the new features for 4.2.
What’s missing from most of these tone curve discussions is characterization of the tone curve itself. When you read the seminal literature about filmic-type curves, the attention is directed at the toe, sloped such to “crisp” the darkest tones. Sigmoid, to my limited understanding, doesn’t push highlights to saturation as quickly. And so on…
All this “gamut protection”, “exposure”, and “black/white” is secondary, or worse, to the above…
Thanks for developing the sigmoid module. I look forward to testing it and reading the documentation when it is prepared. At least the answers here have got me started. I am also sure as it is becomes implemented in the various builds there will be some constructive discussions and examples showing both the strengths and weaknesses of Sigmoid and Filmic options for tone mapping.
This is underway in the main discussion which got long and the new one I started for posts that were evaluating the sigmoid module…so this is well underway… I think the real thing that will come to light is filmic fatigue. People might be thinking oh no not another tone mapping module to master expecting a lot of reading and theory. I think ease of use will be the real strength of this module. Where filmic was involved and technically precise and there were many additions renditions, fixes and nuances, sigmoid will be much simpler and straightforward out of the gate.
Because there were so many features in filmic many people were trying to get a finished image from it. This often led to endless rounds of tweaking all the various parameters and then coupling this with how filmic was implemented with various desaturation and hue preservation I think left some people chasing their tail cycling through combinations of settings. In fact for many instances really it could have just been left in default activated with maybe a tweak of the white relative to do its job as a global tone mapping edit… This is an over simplification but I think you will see that you will enable sigmoid…you might be happy right away. Then jig contrast a little and if necessary skew. I think @Jandren has mentioned to use this more as a touch up or final tweak near the end of the edit. Likely for a few images you will try the color pres at 0 ,50, and 100 to see what it does and decide then how to use it in the image… so very easy. One thing mentioned was the suggestion by @Jandren to use the contrast slider in rgb CB with the module to add contrast. I have often done this any way even though it was not generally recommended. I found that something between 0-10 % was always a nice tweak and helped to avoid pushing local contrast too hard but that could just be my taste for contrast. So far I have not noticed any weird artifacts or unpredictable color issues. The sliders pretty much do what you would expect. Tone eq will likely be useful when highlights are blown or maybe this will prove to be the time for filmic with its extra tools and control… I guess the point of my comments are that filmic suffered all the slings and arrows of transitioning away from a base curve and display referred workflow that lead to all that “this doesn’t look like my jpg” stuff. I think it also came with the new changes and module of color calibration and rgb color balance and diffuse and sharpen and now HLR etc etc… all of which had their own issues that could be impact filmic and the reverse. So I think getting used to Sigmoid will be far less involved with its simplicity and coming in to this more stable platform and this will make some happy and others will likely prefer to stick with filmic and the level of control it provides along with how they have come to master it…
Personally, my workflow with filmic is a matter of a few seconds per image, so I find it fairly easy to use. I don’t object to sigmoid but I don’t really intend to use it.
Agreed.