Re: [Gimp-developer] the Gimp lcms.c plug-in

[Øyvind Kolås <pippin gimp org>]

On Fri, Jul 20, 2012 at 11:46 PM, Elle Stone <l elle stone gmail com> wrote:
> Hi, John,
> By "native space" do you mean whatever color space the image > 1. Is my impression correct? Is Gimp planning to use a very large
> internal working space for all image manipulation? If the answer is
> "No", ignore questions 2, 3, and 4.

Yep, implicit in GEGL and babls architectures is making intermediate
results be stored in buffers of floating point precision without
clamping/etc at the gamut (allowing as wide gamut as needed by the
data)

> 2. If so, is that color space something like scRGB mentioned in the
> Wikipedia article?

It is similar - best summed up, it is RGB stored with linear/physical
light - using the sRGB RGB primaries - stored as half or single
precision floating point (not 8bit or 15/16bit per component fixed
point).

> 3. If so, what about shadow detail (a problem mentioned in the
> Wikipedia article)?

That sounds like a problem only relevant to low bidepth fixed point
representations.

> 4. If so, will there still be a need for ICC profile conversions (I
> can't imagine what the alternative might be, but that doesn't mean
> there isn't an alternative) from the image's "native space" (if I
> understand your usage of the phrase correctly) to Gimp's very large
> internal working space (and back out to whatever output space the user
> wants upon exporting the image, and also to display the image on the
> monitor screen)?

As we move along towards embracing a fully GEGLified workflow,
different things will happen at different times. The initial thing to
reach for is likely to support the 2.8 era manual colormanagement.
With a fully GEGLified system there will still be the need to use ICC
based conversions to pixel formats efficiently dealt with by
babl/GEGL/GIMP as well as do final transforms for display / export.

/Øyvind K.
.--
«The future is already here. It's just not very evenly distributed»
                                                 -- William Gibson
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