[Gimp-developer] Adding better LCH support to GIMP 2.10

[Elle Stone <ellestone ninedegreesbelow com>]

GIMP's new LCH blend modes are wonderful. But trying to use these new 
blend modes without the proper supporting tools is sort of like being 
given a new Aston-Martin with a 35-mile-per-hour governor on the engine.

To make the LCH blend modes truly useful GIMP needs:

* an LCH Hue-Chroma tool.
* LCH color sliders added to the "Change Foreground Color" dialog.
* the Luminance blend mode in addition to the LCH Lightness blend mode.

There are already more or less useable patches for the LCH Hue-Chroma 
tool and LCH color sliders 
(https://bugzilla.gnome.org/show_bug.cgi?id=749902), and for the 
Luminance blend mode (https://bugzilla.gnome.org/show_bug.cgi?id=753163).

Adding the LCH Hue-Chroma tool and LCH color picker sliders for GIMP 
2.10, right alongside the eventually-to-be-deprecated(?) HSV 
Hue-Saturation tool and HSV color picker sliders, would allow GIMP users 
a chance to adapt to LCH before HSV is summarily removed from the UI.

Best,
Elle

How to split tone digital images using LCH and Luminance blend modes
http://ninedegreesbelow.com/photography/split-toning-using-LCH-blend-modes.html