[Openicc] Promoting colormanagement for LINUX

[Stefan Döhla]

Am 13.02.2008 um 23:54 schrieb Graeme Gill:

> Hal V. Engel wrote:
>
>> I think that we need to keep in mind that all of these DEs and  
>> widget sets are
>> built on top of X11 and that X11 is the software layer that is  
>> common to all
>> DEs and window managers in the open source arena.  Anything that is  
>> done to
>> improve CM in X11 benefits all of these tools where as improvements  
>> made in
>> KDE or Gnome or QT or GTK... only benefit a subset of users/ 
>> applications.
>
> Hmm. I think the X11 folks have decided that CM is exactly NOT what  
> X11
> should be doing, at least going by the "State of X" google talk.
> See <http://www.youtube.com/watch?v=-oFxhqYn-g0> at the 17:00 mark.
>
for the interested people: at ~ minute 17.

> And to a fair degree I think they are right. There might well
> be architectural reasons for placing certain parts of the
> functionality in the X server, but the primary issues with
> doing this at the moment is the standards one. Color isn't a
> done technology that everyone agrees on. Build something like
> a current CMM into the X server, and it will only be a short
> while before people are fretting about how it then locks them
> into an "old fashioned" work flow for old hardware and old
> applications, and is an "extra layer of complexity" that has
> to be bypassed.
>

One thing that would ease implementing basic color management: Trust  
the X-server that it renders a colour in a predictable way. This is  
the MS approach: assume sRGB for everything and tell the apps that,  
well, it's not sRGB and you are better off doing this inside the  
application. If the combination OS and video card were smarter all  
colours would be mapped from sRGB to the monitor color space.

My guess is the reasons for this missing link are
- 'extra layer of complexity' that you mentioned - probably not, if  
the video card could do it
- 8bit problem: once you do the conversion always people will get  
anoyed by the introduced loss of gradients etc. - probably no more  
once 16bits per channel are common and scRGB is the assumed color space
- how do you tell old color-managed apps that their job is done  
already and you can only give sRGB/scRGB to the OS? I haven't read the  
MS documentation but I would assume they have a per-application switch  
that programmers must use to activate a software based color conversion.

MS is on a good way making this system work - although I don't think  
that companies that have the old system with internal ICC color  
management working will switch soon.

My impression is that X11 will not go this way since they don't want  
to deal with color conversion inside the server - especially if this  
is something that is configured externally (i.e. by profiles) which  
adds dependencies and internal complexity.

- Stefan