Re: [Gimp-developer] Don't make an architectural mistake based on a groundless premise

[Elle Stone <ellestone ninedegreesbelow com>]

On 10/04/2014 11:59 AM, Øyvind Kolås wrote:
> On Sat, Oct 4, 2014 at 2:46 PM, Elle Stone
> <ellestone ninedegreesbelow com> wrote:
> > Based on the groundless premise that editing operations should
produce the
> > same results when performed on the same colorimetric colors, ..
>
> No;

I'm not sure what you are saying "No" to. Here are excerpts from 
previous posts that you've made talking about the matter:
http://article.gmane.org/gmane.comp.video.gimp.devel/19916
> My stance is that the sliders on an
> operations should be predictable and always do the same thing for the
> colorimetrically absolute same color
http://markmail.org/message/n6ttql3ajtjbe767
> GEGLs image processing is intended to all operate in device independent
> color spaces, no matter which camera you took a picture with
> gaussian blurs, color adjustments etc, should behave the same.


> No; but same parameters for same input colors producing same results
> is considered desirable behavior. Predictable interfaces are nice
> interfaces.

In a properly color managed image editor, the way for a user to get 
predictable editing results is to set up a consistent workflow based on 
the RGB working spaces that the user finds appropriate for the tasks at 
hand.

Edit 50 ProPhotoRGB images in a row and results will be predictable for 
anyone using a ProPhotoRGB workflow.

Edit 50 sRGB images in a row and results will be predictable for anyone 
using an sRGB workflow.

The real question is why anyone would want to edit ProPhotoRGB images in 
GIMP, given GIMP's sRGB "PCS". Results certainly won't be consistent 
with editing ProPhotoRGB images in any other image editor.

Instead, after converting the ProPhotoRGB image to GIMP's sRGB "PCS", 
editing results will depend entirely on how many operations the GIMP 
devs choose to "special case" by converting to a target profile made 
using ProPhotoRGB primaries, as seems to now be the plan for "multiply".

Until GIMP is properly color managed, the only users who might find GIMP 
editing results predictable are users who already only edit their images 
in the sRGB color space.

Respectfully,
Elle Stone
--
http://ninedegreesbelow.com
Color management and free/libre photography