Re: [Gimp-user] [Gimp-developer] GIMP should fork babl and GEGL

[Elle Stone <ellestone ninedegreesbelow com>]

In his last post on the topic Pippin said:
> Once we have the vocabulary to also describe this aspect of the
> pixelformats used by operations, the first thing we should do is to
> annotate all the operations which are broken when done with sRGB
> primaries, then we will be able to continue refactoring, profiling and
> optimizing; without breaking existing functionality/rendering. Not
> only in terms of making more operations request directly userRGB, but
> also doing things like make some linear operations accept any of
> userRGB or bablRGB (or other linear RGB); and creating output buffers
> in the same format – to avoid unnecessary conversions in such cases.
>
> Using a fixed linear RGB format instead of userRGB is what for some
> operations will provide the consistent results for the same property
> values / slider positions. Knowing which operations this is important
> for is easier to determine when we have code providing the vocabulary
> in babl. The further along on the roadmap, more of the road will have
> to be laid/determined as we walk it.

Nothing in the above post shows that Pippin has given up on unbounded 
sRGB. If Pippin really understood anything I've been trying to explain, 
he wouldn't still be saying things like:

//begin quote
"Using a fixed linear RGB format instead of userRGB is what for some 
operations will provide the consistent results for the same property 
values / slider positions. Knowing which operations this is important 
for is easier to determine when we have code providing the vocabulary in 
babl."
//end quote

There is not one single operation for which it is important that sliders 
produce consistent results. NONE. NOT ONE. The whole premise that 
sliders should produce consistent results is grounded in a misconception 
of the requirements for RGB image editing.

Anyone not indoctrinated in the whole unbounded sRGB mystique that's 
been perpetrated among the babl/GEGL/GIMP devs for the last however many 
years would be rolling on the floor laughing if they could fight their 
way past the nonstandard "color management" vocabulary enough to 
understand what you all have been talking about all these years.

I no longer have the time to continue being actively involved with GIMP 
development (OK, that cheering in the background isn't nice! :) ). My 
hope is to see the whole unbounded sRGB thing abandoned. Let bablRGB be 
UserRGB. You can deal with device-specific code with a UI warning. An 
RGB image editor should NEVER mess with the user's RGB data without the 
user's explicit request. Behind the scenes conversions to unbounded sRGB 
is just wrong.

GIMP is important to free/libre artists. GIMP is also important to 
would-be refugees from Adobe Cloud. Artists need non-proprietary 
alternatives and specifically they need software that doesn't lock the 
user's work inside proprietary formats that can't even be accessed 
without a subscription.

(To forestall one of Pippin's stock responses, no, I am not advocating 
that GIMP be a PhotoShop clone. One reason I switched to Linux and free 
software was because I was unhappy with PhotoShop limitations regarding 
linear gamma image processing; sadly Cinepaint capabilities were 
overrated; even more sadly, all these years later GIMP high bit depth 
image processing is saddled with the whole unbounded sRGB overlay.)

If GIMP can't get ICC profile color management exactly right, well, 
DarkTable partly fills the gap with its built-in masks. And Krita is 
frankly leaving GIMP in the dust in very many ways. Krita is a load of 
fun to use for painting. But Krita not aimed at photographers and it's 
not as easy to use for strictly RGB image editing as GIMP would be, 
could be, if unbounded sRGB is just abandoned and the devs starting 
listening to potential and actual GIMP users.

What free/libre photographers really need is for GIMP to be everything 
it could be if ICC profile color management is properly implemented 
across the board for all editing operations. This whole unbounded sRGB 
thing is a dead-end street.

Best regards,
Elle Stone