[Openicc] GIMP color management

[Jan-Peter Homann]

Hello Bob, hello list
Working with digital color since the late 80ties on AMIGA and later 
focused on Mac OS and Windows (if not avoidable...) let made me 
following experience:

In the field of colormanagement, programmers of applications, OS and 
printing environments often invented the wheel several times itself. At 
the end the user had a car with 11 wheels of different sizes and needed 
a mechanican to make it driving.

Observing the development of LINUX, it seems that the community needs to 
make the same experiences...
A definition of expected behavior and a testsuite seems to be a very 
good idea to lead the user through the jungle of different environments.

What are the basics from my view:

A) Central place incl. chooser for:
----------------------------
- Monitor profile
- RGB-workingspace profiles
- CMYK-workingspace-profiles
- standard CMM (littleCMS, Argyllcms)


B) Definitions of expected behavior:
---------------------------------------

An application / library should be use
- monitor profile
- RGB-working space profile
- CMYK workingspace profile (if necessary for the intended use)
- standardCMM
- embedd the actual working space during file-save
- use an embedded profile during file-save

A printing environment should be use
- RGB workingspace for RGB-files without embedded profile
- CMYK workingspace for CMYK-files without embedded profile
- use embedded profile instead default working-space
- standardCMM for color transformation to the printing colorspace
- the profiles for the printer should be connected to the settings for 
printertype, printing media, other driver settings


C Testsuite / procedures
------------------------
application->Monitor:
- Changing between very different monitor-profiles on system level 
should lead to different color appeareance on monitor
- changing between differnt working spaces on systemlevel should lead to 
different color appereance on monitor (for files without embedded profile)
- using files with different embedded profiles should lead to different 
color appereance on monitor

application->printing environment:
- Changing between very different printer-profiles (in the printer 
driver) should lead to different color appereance at printing output
- changing between different working spaces on systemlevel should lead 
to different color appereance at printing output (for files without 
embedded profile)
- using files with different embedded profiles should lead to different 
color appereance at printing output


This would be some easy tests, if applications / libraries and printing 
environments are able to recognise central color settings on system 
level and embedded profiles in files.

As the profiles on system level are connected to the standardCMM, the
proper use of intents and profiles itself can tested seperatly.

If somebody plans to make such testsuite, I would be able to deliver 
profiles, which leads to very different visual appeareance.

---

Some time ago, the gimp-print team announced at the colorsync 
mailing-list, that they plan to implement more colormanagement 
functionality.
In my view, it would nice, when both GIMP and GIMPprint can use a 
system-setting for RGB- and CMYK-workingspace, a standardCMM on 
systemlevel and communicate together. This would may lead other teams 
also to use this mechanics instead of inventing their own 
colormanagement-wheel.


:-) Jan-Peter



Bob Friesenhahn schrieb:
> On Sun, 20 Feb 2005, Jan-Peter Homann wrote:
> 
>>
  The best we can hope
> for is a an application agnostic framework or library which can be used 
> to enhance existing rendering environments with color management.  Even 
> if this is not achieved, a standard of operation and a standard way to 
> install color profiles and describe the local color management 
> intentions/process would be a great benefit to the community. A 
> compliance test suite (inputs and expected output) would also be a benefit.
> 
> Ultimately the user should not need to care if she is using Gnome/Gdk, 
> KDE/Qt, gimp-print, VTK, OpenGL, ImageMagick, libart, imlib, GD, X11, 
> Ghostscript, Mozilla, SVG, CinePaint, GIMP, or any other combination of 
> software environments.  As long as there is a definition of expected 
> behavior, and verified compliance to that definition, then the user can 
> expect correct behavior.
> 
> Bob
> ======================================
> Bob Friesenhahn
> bfriesen at simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
> GraphicsMagick Maintainer,    http://www.GraphicsMagick.or
> g/
> 
> 
> ------------------------------------------------------------------------
> 
> _______________________________________________
> openicc mailing list
> openicc at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/openicc


-- 
--

homann colormanagement ------ fon/fax +49 30 611 075 18
Jan-Peter Homann ------------- mobile +49 171 54 70 358
Kastanienallee 71 ------- http://www.colormanagement.de
10435 Berlin --------- mailto:homann at colormanagement.de