Features/CUPS colord Support

= CUPS colord Support =

Summary
ICC profile support for printing. Color management will be applied to printed jobs at the rasterization step.

This can lead to improved color fidelity in printed output.

Owner

 * Name: Tim Waugh


 * Email: twaugh@redhat.com

Current status

 * Targeted release: Fedora 17
 * Last updated: 2012-02-07
 * Percentage of completion: 100%

Detailed Description
The idea is for CUPS to apply ICC profiles to print jobs when converting them to a raster format. It uses colord to determine the correct profile to apply, and the gstoraster filter applies the profile to the job.

Benefit to Fedora
A properly color managed system will provide better color fidelity from screen to print.

Scope
Most of the work is already in place. The main part remaining is testing.

How To Test
For "real world" testing, something like a colormunki is required. Does anyone have one of these?

A more accessible way of testing this feature is to use test profiles which are obviously wrong in some particular way (e.g. inverted), as a visual method for determining that a particular profile was in fact applied. One example is /usr/share/color/icc/FakeBRG.icc from the shared-color-profiles package, which swaps red to green, blue to red, and green to blue.

We need to test that:


 * No profile is applied when there is no profile to apply; i.e. the common case of a user who has taken no action to set up color management, using a printer for which no standard ICC profile is available
 * The profile is applied when there is a single profile specified in the PPD file with the CUPS PPD extension
 * The correct profile is applied when there are several available, each for a specific resolution, color space, and media type
 * User is able to override the profile used by using the "Color" System Settings tool
 * Warnings/errors in /var/log/cups/error_log are kept to a minimum

User Experience
Without an ICC profile set for a queue: no change.

With an ICC profile set for a queue: better color fidelity.

Dependencies
colord

Contingency Plan
In the worst case, the icc patch can be removed from the cups package.

Documentation
http://www.freedesktop.org/software/colord/

Release Notes
ICC profiles (for color management) are now applied to print jobs if available.

Comments and Discussion

 * See Talk:Features/CUPS_colord_Support