Bug 251683

Summary: Can not reduce saturation of 'only red'.
Product: [Applications] digikam Reporter: Jagdeesh Deshpande <jagdeeshdeshpande>
Component: Plugin-Editor-GmicQtAssignee: Digikam Developers <digikam-bugs-null>
Status: RESOLVED FIXED    
Severity: wishlist CC: caulier.gilles, nvlplx
Priority: NOR    
Version: 1.4.0   
Target Milestone: ---   
Platform: unspecified   
OS: Linux   
Latest Commit: Version Fixed In: 8.1.0

Description Jagdeesh Deshpande 2010-09-18 20:23:41 UTC 
Version:           1.4.0 (using KDE 4.5.1) 
OS:                Linux

 In editor, with Color> Hue/Saturation/Lightness>Channel Red (in the drop-down list), I can not reduce saturation of only 'Red' channel.This reduces saturation of all channels in spite of selecting either Luminosity or Red or Green or Blue in the drop-down list.
My Nikon D40 gives much saturated (red) skin in portrait mode.
So without affecting any other color,saturation of red is to be reduced to adjust skin tone.
This is very easily possible in GIMP by selecting 'red instead of default master' in the 'hue-saturation tool' and reducing it's saturation.


Reproducible: Always

Steps to Reproduce:
Open in editor any portrait having background or objects of other than skin color.
Now at Color> Hue/Saturation/Lightness>Channel Red (in the drop-down list),reduce saturation  to say (-)30. 


Actual Results:  
Saturation of all the  colors  gets reduced,not of only 'red'.

Expected Results:  
Saturation of 'only red' should get reduced. 

Moreover,instead of channel,it should work on 'ranges/bands of hue' as in GIMP.In GIMP user can select any of 7 among 1 Master+6 hues;i.e.red,magenta,blue,cyan,green & yellow.
A slider for 'overlap' is also provided. 
But in GIMP we can not select any 2 at a time i.e. selecting red and yellow is not possible at one go.
Comment 1 nvlplx 2010-11-14 21:47:14 UTC 
I'm agree with this suggestion. 
The HSL toolbar should show multiple sliders, one for each "canal" (i.e. red, blue, green, yellow, cyan, magenta... at least), like in other photographic editing software (like Photosphop and Aperture). 

It's the last main feature that lacks in the digikam image editor ! (ok, ok, it lacks local photo editing too... but I think this is pretty much complicated... and not so commonly usefull that precily saturation adjust).
Comment 2 caulier.gilles 2023-05-10 20:29:51 UTC 
The GmicQt Colors/Hue Lighten-Darken tool is typically what's you need.

See the online documentation for details :

https://docs.digikam.org/en/image_editor/enhancement_tools.html#g-mic-qt-tool

Gilles Caulier