@heckflosse Why not allow free combinations according to a predefined list of algorithm sharpness? Simply check that the high contrast algorithm is “sharper” than the low contrast algorithm, and users won’t have weird results. It would save you the trouble of finding use cases for all the combinations, and make it easy to add more algorithms in future.
Thanks to @gaaned92 I was able to complete compiling RT for my use, and also thank you to @plaven for turning me on to it. I’m very noob in this regard, although I have been using the stable releases of RT for years now from the download page. Please excuse me! Finally I can show an AMaZE+VNG4 vs DCB comparison.
AMaZE+VNG4 on the left, DCB on the right.
Here is the raw file again (I’ve forgotten if it was still on the other thread or not)
_MG_1571.CR2 (25.3 MB)
The screenshot shows the sharpening settings that was used. Indeed less aggressive sharpening would exaggerate the diagonal artifacts less, but nontheless the artifacts are present. DCB just looks much better. @heckflosse Ingo, I hope this example helps to rest the case. 
@samuelchia
I regularly make builds for W64 of all development live branches available at RTW64NightlyBuilds/ – Keybase.pub
I added DCB+VNG4 and RCD+VNG4
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Since there is the contrast threshold adjuster for sharpening, I use much more aggressive settings
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Thanks!
In this image (noisy, as usually are mine), I attacked noise before applying your steps. That is, I worked in Amaze as I’d normally do and applied either Denoise and Wavelet Denoise and Refine. Denoising an image such as that ends up with a significant lost of detail.
After applying your steps, the detail is back almost entirely, and without any apparent noise increase.
Screenshot with before (left, neutral profile) and after (denoise + heckflosse sharpen):
Just in case, here’s the Creative Commons, By-Attribution, Share-Alike licensed raw: CRW_3783.DNG (17.8 MB)
CRW_3785.DNG.pp3 (10.3 KB)
My question is: since this relies on changing the demosaic method, should all these steps be applied at the beginning of the workflow? Or, as usual, apply them at the end of the raw workflow? Or should I only change the demosaic method first, then do the usual edits, and finally do the rest of heckflosse sharpening steps?
I just added xtrans 2-pass (combination of xtrans 1-pass and xtrans fast)
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Since there is the contrast threshold adjuster for sharpening, I use much more aggressive settings
But the threshold only works by masking away things that are soft. What if one could also mask away things that already are sharp enough? Would that be possible? Does it even make sense to do so?
Great idea about the x-trans 2-pass. The other day I was thinking that with this new compound demosaicing method, 3-pass sharpening for x-trans could be less useful (or at least, less often needed).
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That would also be possible. Whether it makes sense, I don’t know atm…
Sébastien, currently the xtrans method names showed in gui are:
"4-pass",
"3-pass (best)",
"2-pass",
"1-pass (medium)",
"fast",
"mono",
"none"
which is not correct anymore as 3-pass is not the best imho. Can you, being an xtrans user, suggest better method names?
Info, maybe the 1-pass and 3-pass choices can be renamed to something like “1-pass (Markesteijn)” and “3-pass (Markesteijn)”. And 2-pass could be renamed “fast + 1-pass”, and 4-pass “fast + 3-pass”.
Sébastien, to keep things consistent with bayer demosaicers (where the flat demosaic algorithm is the second in the name), would you also agree with
1-pass + fast
3-pass + fast
?
How about family pass or season pass? 
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Joking aside, for consistency, maybe:
1-pass+fast
3-pass+fast
If you like add (combo), (hybrid), (dual), or whatever next to it.
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Done.
Hi @heckflosse
I just opened a bug for you : Artifacts appears sometime when using Highlight reconstruction Colour propagation together with the combined xtrans demosaicers · Issue #4639 · Beep6581/RawTherapee · GitHub
I get sometimes artifacts while playing with the contrast slider.
It could make sense if you are trying to even out the sharpness across the entire image. Usually the corners and edges are less sharp than the center. And most lenses are not radially symmetrical in sharpness either.
The other case for protecting edges that are already very sharp is to avoid the development of sharpening halos and/or clipping of the pixels along the edge.
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