There are some bug reports listed below that pertain to color management and color mixing, that I would very much like to see be put on the "milestone 2.10" list. Here's why:

I just posted a tutorial on using GIMP to make an illustration from a photograph:
http://ninedegreesbelow.com/photography/leaves-in-may-illustration-from-photograph.html

If you look at the articles on my website (http://ninedegreesbelow.com/photography/articles.html), there are a bunch of articles on using high bit depth GIMP, because high bit depth GIMP is my favorite image editor ever, hands down more useful than PhotoShop ever was (though I dearly miss having adjustment layers).

Personally I don't use default GIMP 2.9 for editing, but rather a patched version of GIMP
(http://ninedegreesbelow.com/photography/patched-gimp-compared-to-default-gimp.html).

When I write a tutorial on using GIMP, I try to include information on using default GIMP as well as my patched version of GIMP. But I keep running into the same problems with trying to edit using default GIMP:

* No LCH color pickers and no LCH Hue-Chroma tool (https://bugzilla.gnome.org/show_bug.cgi?id=749902)

* No Luminance blend mode (https://bugzilla.gnome.org/show_bug.cgi?id=753163).

* No easy way to make Curves and Levels adjustments on linear RGB (https://bugzilla.gnome.org/show_bug.cgi?id=757444)

* No obvious way to invert colors on linear RGB (https://bugzilla.gnome.org/show_bug.cgi?id=757686).

* No easy way to draw a gradient using linear RGB (https://bugzilla.gnome.org/show_bug.cgi?id=735897).

* No easy way to correctly decompose to LAB/LCH and then be able to drag layers back to the layer stack
(https://bugzilla.gnome.org/show_bug.cgi?id=765178 - also affects my patched GIMP, except I disabled decompose altogether for unrelated reasons).

* No easy way to correctly extract LAB/LCH channels as layers (https://bugzilla.gnome.org/show_bug.cgi?id=755376 - also affects my patched GIMP).

If the above issues were fixed, then default GIMP would be very useable for following the steps in my tutorials as long as the user sticks with the built-in sRGB color space. And I could go through my tutorials and remove passages like "here's the workaround for default GIMP", "here's how to get the right LAB/LCH layers", "the workaround for default GIMP is too complicated to explain in this tutorial", and so forth.

And then I think the only remaining major advantage my patched GIMP would have over default GIMP would be the ability to edit in user-chosen RGB working spaces. Well, that and I've unclamped a few additional blend modes and etc, to make some VFX people happy (and this unclamping turns out to be useful for general editing).

Going beyond the fact that I'd really like to rewrite my GIMP tutorials to sound less critical of default GIMP, the above-listed bug reports fall into three fairly important categories:

1. Allow GIMP users to take full advantage of LCH blend modes, which is something I don't think any other image editors yet provide.

2. Allow GIMP users to produce radiometrically correct results for editing operations that affect tonality. Right now GIMP users get gamma artifacts every time they use Levels or Curves or invert colors, and they have to resort to workarounds to draw a linear gamma gradient. For an image editor that purports to make radiometrically correct editing results easy to produce, this is an unfortunate situation.

3. Fix GIMP's handling of LAB/LCH decompose and GEGL's extract component, so that GIMP users will be able to use LAB/LCH layers and actually get correct results from drag and drop and such.

I realize that developer time is limited, and of course I'm willing to help update and test patches for the above bug reports.

I also realize that everyone thinks their own bugs are "the most important", and perhaps I'm overestimating the importance of the above bugs (but I don't think I am). But like I said, I keep running into the same issues every time I try to use default GIMP, so I thought I'd at least make a post on the subject.

Best, Elle

http://ninedegreesbelow.com
Color management and free/libre photography

Your wish is my command, she said responding to IRC!

A compact list:

* No LCH color pickers and no LCH Hue-Chroma tool (https://bugzilla.gnome.org/show_bug.cgi?id=749902)

* No Luminance blend mode (https://bugzilla.gnome.org/show_bug.cgi?id=753163).

* No easy way to make Curves and Levels adjustments on linear RGB (https://bugzilla.gnome.org/show_bug.cgi?id=757444)

* No obvious way to invert colors on linear RGB (https://bugzilla.gnome.org/show_bug.cgi?id=757686).

* No easy way to draw a gradient using linear RGB (https://bugzilla.gnome.org/show_bug.cgi?id=735897).

* No easy way to correctly decompose to LAB/LCH and then be able to drag layers back to the layer stack
(https://bugzilla.gnome.org/show_bug.cgi?id=765178.

* No easy way to correctly extract LAB/LCH channels as layers (https://bugzilla.gnome.org/show_bug.cgi?id=755376).

Best, Elle