Hello,
Thank you for your reply,
that is exactly why I created this fork, so that it would be 100% independent of darktable.
That is exactly my philosophy, and I strive to stick to it; however, we are only human, and mistakes can still happen…
Greetings from the Luberon, 
Christian
That is wonderful news! I am really looking forward to integrating that in my workflow 
And, for the record and as I also repeated above, I am also fully supportive of your work, and - it goes without saying - you do it how you like. My remarks are purely selfish: I like what I see and I would like to be able to use it for real, not just to play with it in a sandbox.
What I like about your fork is that it has a different icon to click on and is independent of the ‘official’ darktable. It certainly doesn’t screw with my official DT install. I actually wish the nightly builds could be done in a similar way, but I presume it is not practically as it is the pathway for the next stable release.
What really concerns me in this discussion is the way Christian-B is being treated. He’s willingly contributing his ideas, dedicating his time to implementation, and providing a proof of concept. I find comments like “flood the zone with shit” unacceptable in this context, regardless of what the poster may have actually intended.
This “shit” comment was also liked twice and subsequently received no critical feedback. Anyone who reads the forum closely will notice that not everyone who voluntarily shares their ideas with code here is treated so disparagingly.
A critical discussion on the matter is always fine, and the vast majority of forum participants adhere to this when it comes to my concerns.
For those who don’t understand my comment: it’s simply a call for more kindness and consideration toward one another. And not without self-interest. In the future, I’d like to be able to choose from a wide range of modules in darktable and use the best ones for myself.
I would like to echo your thoughts …
I’m wondering what you see as the risk. Pls correct me if I’m wrong but you can run DT with any config and cache settings, and this means your production setup (with its own config and cache) is safe.
Thanks @Christian-B for sharing this experimental testbed fork. It’s a really good way for folks to test, play around, and provide feedback without impacting their production version of DT.
I’ve tried the spectral tone controls. The built in presets are a good start for modifications.
How are those presets defined? When I choose a preset I don’t see any change in any of the sliders.
Are there any instructions or tips we need to know about using the module?
I’m using the AppImage on Ubuntu 26.04.
Just stay cool 
If you re-read that sentence in it’s context, it’s not offending at all.
Everyone is absolutely free to do any code developing in the personal branch. All devs do that, we all likely have a number of branches/commits for personal use that we don’t publish for several reasons. (I just counted here, there are 9 and i don’t know how/where those will end.
But if there is some idea / code piece that someone wants to be integrated in dt, the chances are almost zero if there isn’t a PR that works “as is” without rebasing work on current dt master. Otherwise reviewing simply wouldn’t work at all and chances for a seriously-buggy master (thus also the daily/weekly build so many are using for daily work) would be pretty high. Nothing crazy or bad-minded, just practical.
I am looking forward for PR’s, especially interested what you did on color equalizer @Christian-B
don’t pull oil into a fire - no one beside you in your comment brought the contribution of Christian-B ito the same context as “shit”
If you are interested in a critical discussion, then try to be critical to your posts first …
I agree. Christian is also doing some innovative work and bringing it to maturity before creating a PR request. We saw AgX get developed in this manner and it is a sensible approach.
He added a control similar to the tone eq where you can hover on the screen and scroll to change that color
Hi Jens-Hanno
I invite you to read this post: Color Eq & Mouse moved
This is an idea we discussed together on GitHub when you were working on developing the module.
Greetings from the Luberon, 
Christian
@Christian-B, I think you may want to get some feedback on the use of your Spectral Tone module. Since the Windows version is working again, I tested it on a few images and compared to AgX and your Basecurve. I wanted to know
a) whether I can get a pleasing look with each module and b) how easy it is to get there. For that I either first developed an image with AgX than made a copy and switched to (and tweaked) one of your tone mappers, or I made a duplicate original and developed from scratch with the new tone mapper.
I could get a pleasing look with all three tone mappers. AgX is most familiar to me as it is my default since about a year and I know what sliders to use. With Spectral it was also quite easy to understand which slider to pick for a desired effect. It seems to be a ‘gentle’ module with a smooth roll off into highlights which I think was your intention. It gives a brighter image per default compared to AgX, just default settings without any other development step. It may well become my favorite tone mapper, at least for certain images. With Basecurve I have more difficulties to pick the sliders.
Hello,
I’d like to thank EVERYONE who has contributed to this thread. Unfortunately, I don’t have much time right now, but I’d like this thread to get back on track and focus on its main topic: the module itself.
Best regards,
Christian
I’ll try to recreate it because I think I lost it but I tried this module on the sunflower in the window image and I was really impressed with the result I got and with your highlight controls the range of yellows I could get on the image was really nice
I think you can get a working version from here (also W11). It is somewhat unstable as it crashes from time to time but I couldn’t figure out what triggers the crash.
I have used it a fair little bit since the WIndows bug was sorted and no crashes but I will keep my eye out…what I lost was the edit if your post was directed at me…
I’m running it with debugging so I can report on any issues…
Hello,
Just a heads-up: I’ve made a small update regarding the desaturation of highlights.
I created this tag while I was working on the Windows version.
The module is now available in the “main” branch.
The current presets are just the default settings. I still need to work on them.
I’m going to write a short user guide and a description of the different sliders.
You’ll already find a brief description in the tooltips.
That’s a lovely compliment—it’s exactly what I was aiming for: an easy-to-use module with a softer, “film photography” look.
While it has its own distinct character, it’s such a subjective matter that I don’t think it’s necessary for different tone mapping options to produce the same result.
Good question. Rec.2020 is not the working space of the module itself. It is simply the wide-gamut RGB representation provided by darktable’s scene-referred pipeline before conversion to XYZ. The module immediately converts that signal into CIE XYZ D50, where the core tone and gamut operations are performed.
Because Rec.2020 is a very wide-gamut RGB space, highly saturated colours and specular highlights are less likely to be clipped before reaching the tone-mapping stage. Early RGB clipping destroys chromaticity information that the subsequent XYZ-based gamut compression relies on.
The signal is transformed through a Rec.2020→XYZ conversion followed by Bradford chromatic adaptation (D65→D50), bringing it into a D50-adapted XYZ working space. From that point onward, tone-scale and gamut processing are performed in XYZ, with conversion back to RGB occurring only at the final stage.
Greetings from the Luberon,
Christian
Thanks, I feel much better now… 
Working in XYZ intrigues me. May have to try it in rawproc, if i can craft a profile whose destination is XYZ.
Just installed the latest version on Windows 11 and stable so far. I applied some spectral tone adjustments to some already edited raw files. What I really liked was the the mid-tones slider could be used for brightening or darkening mid-tones. It worked really nice. So I thought is this any different to the mid-tones brilliance grading in color balance rgb module. I am pleased to say that your slider performed much nicer having a more restricted adjustment towards mid-tones on the image I tested it.
I am still unsure what problems this module is solving but it seems to give some nice dare I say intuitive sliders to compliment the editing process. I look forward to it being included in the DT master. However, one comment I would make is that some of the slider help tips refer to a curve but no curve is visible to the user. I would find it informative to see a curve and what was happening. I thought the advanced tab would reveal a curve.
EDIT: I just realised I was using this on an image that had AgX as the tone mapper. Is it meant to be a tone mapper in its own right. It did work nicely in synergy with AgX.