Well I would also like to throw my opinion into the mix … but sadly I can´t , as there is no version for Mac OS floating around .
I tried to get it done on my own … meaning implementing this into a DT build , but I am too dumb to get it done .
I just hope you get it done to make it public … for a wider audience to see and work with it .
Regards Andreas
you are aware of the technical base of diffuse and sharpen module?
You might have a look at https://github.com/darktable-org/darktable/pull/7669
I’m glad to hear that you want to go forward with this; but I hope that submitting the PR will not close further rounds of feedback. It’s not even a full week, and I do have to work, and so I haven’t even checked out (in the literal sense: checked out the new commit) this version. From reading your description the last change was quite substantial.
Like this module a lot as it sits with the way I work in a number of photos. I have to say I’m only playing around with sliders at the moment for some great results whereas in the past I have switched to gimp wavelets. I will give it a deep dive when I can. I see it sitting alongside contrast equaliser in my workflow.
Diffuse and sharpen is a module that I’m struggling to get to grips with and that’s probably down to me!
Darktable is great isn’t it.
Hello,
You’re right, the latest changes are quite significant. I wouldn’t dare say how many hours I’ve spent working on this project. Don’t worry, I tend to be hyperactive, but I also like a job well done.
So we’ll take the time needed to refine and validate the various basic and default settings.
Have a good evening in Lubéron,
Christian
Many thanks for your work on this, and I hope we get to see it in a future release in whatever final form it takes.
I have done some testing with it, but I’d like to do a lot more.
In the meantime, I do have some initial feedback on the masks:
The pyramidal breakdown makes a lot of sense and in theory aligns well with what we are used to with Contrast Equalizer. However, in practice, I can’t always reliably predict which wavelet scale I want to work on based on the visualization masks. They are quite clear for fine details but become less clear as we move to the coarser details. At a certain point, the mask just looks like a greyscale image and doesn’t clearly show the detail level being worked on.
I’m not sure if it’s possible, but can we explore 2 colours like the “Detail Threshold” slider in masks (yellow/grey)?
What I think would be ideal is if we can see exactly what detail level we are working on (and what won’t be touched), as well as the level of blurring /edge protection when using the edge protection sliders.
Something like this:
fine details
coarse details with low edge protection:
I’m also interested in what will happen with @Wilecoyote’s and @jandren’s approaches. While some people are rightfully worried about duplication and bloat, as a user I’m usually happy to have lots of choice of modules. I can always hide and ignore the modules I don’t use.
That said, I do think it would be worth offering something different with each module proposal. One area I’m thinking it would be nice to explore more is colour contrast. Contrast Equalizer already has the Chroma tab for this, and there’s actually an old Color Contrast module that only works on green-magenta and blue-yellow. But could this new scene-referred algorithm be used or adapted for colour, with more control on selecting the colours and “hue breadth” to work on?
If you’ll excuse the reference to Lightroom, it does have an interesting feature called the “Variance” slider, which is designed to increase or decrease colour contrast. Essentially, you pick a colour and then you increase or decrease the contrast between that colour and similar colours with the slider.
Not sure if it’s at all possible, but just food for thought.
Was not! Thanks.
I too like modules. 
But is this worry also about the future cost of maintenance?
Maintenance is of course a valid concern, but it’s not something I’m involved in. It’s why I said “as a user” because selfishly I just want as much choice as possible.
It’s like when people on forums are arguing about what products company X should produce. There are always those who say, “they shouldn’t release product A because it will cannibalize sales of product B”. But for me, that’s the company’s problem to solve, not mine. As a consumer, I just want more choice 
.
I have not yet tried this module as I am waiting for it to be merged into the master, but I can see the advantages of being able to visualise the detail levels being worked on.
Just try this portable version I made…unzip in downloads and run…delete the folder when you are done…
You don’t have to do anything…maybe just double check xmp writing is off…
This might never get added or it might be this way you can provide feedback…
I dont have an intention to produce more stuff right now but would like to help @Wilecoyote wrap up a smaller more streamlined module which is possible to extend with color contrast and the like down the road. He seems to be busy with other stuff in life at the moment. We all do this as a hobby so Im skiing and dancing, while waiting for him to have time again
I just installed the version @priort produced and straight away am loving the module. I used a heavy handed micro contrast adjustment on this image and it made it pop in my opinion. Th module feels ready to go in my view after just two images.
After your contrast boost though there is a lot of haloing around the darker edges. Not saying it’s a fault of the module but it looks fairly overboosted with more coarse contrast than detail.
I see double or triple images for some of the smaller twigs. I take it the sidecar is in the jpeg? I’m downloading the raw now to see if there are settings tweaks that get rid of the ghosting.
I do not feel I know the module well enough to advise here.
I do know that I love the module, it’s a joy to use and the results are fairly good. Though I see some haloing others mentioned as well. Love to use it with masks to selectively both enhance and diminish local contrast.
I thank you for making this module and hope to see it soon as an official part of td.
It is a local contrast module. So using it always brings the danger of halos. I don’t know if it is technically possible to avoid this completely. The other local contrst modules have to struggle with tis as well.
There are tools inbuild to avoid it and of course the user have to take care of them.
edited after this post
There is still a tiny bit of haloing. But I think to an extent which everyone can live with.
I like the module in this state.
Agree very much on this, that’s still something I do not yet master, though in one example I reduced it to a great extend. As well as with playing with the scales at which the module operates, it’s the very reason I do not feel free to advise.
But I do know that I really like this module.
Together with color balance rgb I feel this may be (one of) my main tool(s).
Keep in mind that halo formation is inherent in local contrast enhancement:
you brighten the bright side of an edge, and darken the dark side. (pushed to its extreme, you’d get a white pixel next to a black pixel…).
In most cases, the brightening and darkening are spread out over a certain distance. Make that distance and the amount of enhancement large enough and you’ll get a clearly visible halo. Lower the distance and/or the amount, and you’ll still get a halo, but you’ll see it as local contrast enhancement.
So the art of local contrast enhancement is in applying enough of it, over a proper distance, to get the effect you want without the halo…
