I thought that a lab tone curve with flat L curve at 50% worked too but no real advantage over the other solution…It is quite similar to low pass as described…
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Interesting…using the channel method every thing shows “coloured” hue patch even the grey patches which can be say 37 38 38 will show a blue green hue … and black areas 1,1,1 show as blue…
Quite different… I guess there might be use cases for both
Interesting… Your way seems more useful than ours. Kustra’s technique is to create a middle grey layer and switch the blend mode to luminosity. That can also be done with the colorize module and switching the blend mode. She then samples those colors, brings them over to paletton and plays around with the various color harmonies to see which way she wants to push the hues of her pictures.
For me the same key is assigned by default, however once I press it while a drawn mask is selected it just locks the mouse but how does it me allow to pan and zoom when all mouse inputs are ignored (incl. mouse wheel). Am I doing something wrong? 
I also just noticed that panning stopped working while zoomed in at a drawn mask, independendly of the shortcut. I remember some time ago this has been working 
I’m using the latest & greatest master (3.9.0+1072~g3f206c88a).
You can use the navigation box in the image preview for panning and clicking your scroll wheel for zooming…if the a key is not working at the moment
Thanks, I badly needed this feature 
Thank you @priort I think you are making a very valid point here.
Starting with artificial file as a sample - original below
Then - low pass approach
Then Lab curve
Then - parametric mask for hue with c pressed
I don’t know why they are so different. But based on what I am seeing on my monitor
Thank you all for the advice!
The goal was to understand a bit the underlying hues. Kustra’s technique aims to have a better visualization so harmonies can be achieved and an interesting point that she makes is when a color contributing to the harmony is part of the deep shadows. If I was able to understand correctly - such colors - even when not extremely apparent - they do contribute to the perception (by the viewer) in the formed harmonies.
As @s7habo pointed in the videos how to influence color shifts - this all gives a lot of opportunities for adjustments.
Keep in mind that you cannot assign a hue to pure white and black. That could explain some of the differences you see. Then, you can’t just display a hue, you need values for saturation and value/lightness. So either you use fixed values for those (which is what happens in the parametric mask view, I guess) or you have to get them from “somewhere”. Parametric mask seems quite decent on the hue values, with saturation and value at about 0.5?
My settings look like the following:
Sorry I’m dumb. I don’t follow the last paragraph …
Ha. After learning a lot from what you’ve posted on here and on YouTube, I only wish I was as “dumb” as you, Todd. 
Dumb and or up to late in my case
Maybe also my question was dumb, because I wasn’t sure how to phrase it.
Let me ask again with simple words: how can I make my shortcut settings look exactly like yours from your screenshot?
I don’t understand the difference between “active view” and “other views” in the shortcut settings, the documentation also does not mention it, as far as I saw it.
You want this section of the manual.
https://docs.darktable.org/usermanual/3.8/en/darkroom/organization/
Not sure if this helps but if you are in lightable when you invoke preferences that will be the list of "active " view…other views will be for darkroom…if you do the reverse you will see the list switches roles to reflect what was active when you entered the shortcuts menu…is that sort of what you meant??
Yes, that was it, thank you 
I still don’t understand this concept “active view” and “other views”. Why should a shortcut menu depend on whether you invoked it while working in lighttable or darkroom, if the shortcut setting clearly states the view context (lighttable / darkroom / …) already
It may just be the way it is organized but also some very complicated combinations can be used and with devices like digitizing tablets and game controllers…so that may have something to do with it but I can’t say why it is the way it is…it may be that you will be taken there when you define these dynamically so it is to just clearly identify where you have made your selections and clicks rather than from inside the preferences…
The amount of dynamic range you can get with filmic and the tonecurves is really amazing! Thanks @s7habo
@nwinspeare has done a nice video on this feature and how to use it…if you have not seen it that could be worth a look…
Todd, I looked at his profile page, but couldn’t figure out what you are referring to.
