Regarding the missing explanation of LCH, and the tutorials linking to each other, that’s on my “to do” list for when I rewrite the first tutorial. Regarding section C2, you are absolutely right, that figure is far too “busy”, too much going on at once. I will separate out the threads and try again.
Thank you! for taking the time to read these tutorials and make suggestions.
It will be awhile before I can make the next effort at improving the tutorials, both from not typing too much at once to avoid stressing my wrist, and also because for various reasons I decided to swtch from Gentoo and IceWM (which I’ve used for roughly 4 and 10 years now) to OpenSuse and Plasma 5 - that’s a rough transition and I haven’t yet managed to get an Apache test server up and running.
You are absolutely right, the solid magenta is disconcerting to look at. Changing the gamut marker color to black does make it easier to look at, at least for me it’s a better color choice.
Part of the problem is that there are still 8-bit integer variables in the “color the slider and panel” code, so the magenta (or whatever “out of gamut” color you choose) kicks in before it should, thereby covering too much of the sliders. This is something that I think will be fixed before 2.10 is released.
A problem with dithering or blending to make the transition less harsh is that the user would no longer know precisely when/where the colors go out of gamut. Having the option to work with out of gamut colors opens up some very nice editing possibilities, but creates problems when not intended or anticipated. So that sharp line “don’t go past here” serves a purpose.
I’ve been thinking about what might make it easier to use the LCH color tools. An outline marking “in and out of gamut” might be easier to look at than the current magenta color overlay.
It would be really nice to have an actual LCH color wheel, which would necessarily be quite different from an HSV color wheel. I’ve been working on a description of what such a wheel might look like and do, and can share what I’ve come up with if anyone is interested, and of course ideas/input from other GIMP users would be nice.