Re: [Gimp-developer] [Gimp-user] Time to fork BABL and GEGL

[Øyvind Kolås <pippin gimp org>]

On Wed, Nov 19, 2014 at 7:31 PM, Elle Stone
<ellestone ninedegreesbelow com> wrote a lot of text that has been
trimmed away...

I am only going to reply to the issues you seem to have with color
image processing algorithms operating in CIE Lab. My general stance is
that if at all possible, algorithms should operate on linear RGB data.
Some algorithms do however not work well on linear data and expect
more of a perceptually uniform color space to give satisfying results.
Many of the ops fitting this categorization - both in GIMP and GEGL
have been using sRGB; even if academic papers introducing/describing
the algorithms specifies that processing is to be done in CIE Lab.
Such operations might be using division, multiplication, power
functions and other chromaticity dependent arithmetic building blocks.
It is for these type of operations using CIE Lab should be evaluated
rather than UserRGB – just like CIE Lab can be considered for new
color image processing ops that rely on more perceptual uniformity
than linear RGBs provide.

/pippin