Re: [Gimp-developer] GIMP and Adobe RGB (1998)

[Øyvind Kolås <pippin gimp org>]

On Thu, Apr 17, 2014 at 1:08 PM, Elle Stone
<ellestone ninedegreesbelow com> wrote:
> The other day there was an IRC discussion of the possibility of GIMP
> supporting RGB color spaces other than unbounded mode sRGB.
>
> I was surprised to see in the transcript a statement that GIMP shouldn't
> support Adobe RGB (1998).

It makes no sense to import opening files with any particular ICC
profile, by definition unbounded gamut RGB spaces support storing and
manipulating all colors of photo's/imagery of any bounded gamut RGB
spaces. What actual color space/pixel format is being used for
manipulation is a separate concern from how color data is passed
around and actually stored. There are definetely many things to sort
out and many things in GIMP that have are straight ports of the old
8bit/component code; keeping track of the _meta_data_ of an original
color space/gamut/pixel format raster data originated in - and the
ability to to chosen/select operations in that space is something that
fits the strongly color managed architecture of GEGL. While doing
global overrides of some of the internal pixel formats that are
absolutely colorimetrically defined would make it easy to misconfigure
the color settings yielding surprising and inconsistent behavior.

> Adobe RGB (1998) is important for:
>
> * People preparing images for printing

The default GEGL/babl pixel formats in floating point are unbounded;
and personally I think the 16bit formats should be made 4.12 instead
0.16 fixed point to provide adequate headroom/footroom - though with a
predominantely floating point based processing doing this might not be
a huge win.

> * People who save Adobe RGB (1998) camera jpegs

Exporting to any particular bounded RGB gamut; as well as proofing
whether colors are within a gamut should in no way be hampered.

> * People who want or need a small gamut color space that is nonetheless
> larger than the very small sRGB.

The usefulness of the extended range in cyan/green; and how many
perceptually discernable colors you gain compared to sRGB is
questionable.

> A summary rejection of Adobe RGB (1998) ignores the needs and accustomed
> workflows of the many, many photographers who work in the Adobe RGB (1998)
> color space.

Not having saddle adapters as mandatory attachment mechanisms for car
seats ignores the needs and accustomed workflows of horse riders used
to maintain and customize their leather saddles.

/pippin