[Openicc] Print Color Pipeline

[Jan-Peter Homann]

Hello all,

In this e-mail, I will describe a little bit more top view, my thought 
about an open color management architecture, with a focus on the print 
color pipeline.

I still think, that the best place to assign the printer profile to a 
driver setting is the driver itself.
By the way, there is the german company turboprint 
http://www.turboprint.info/ offering printer drivers for
LINUX
Mac OSX
Windows (now in beta)
which allow:
- true CMYK profiling through the driver
- assigning the driver stting specific profiles
- doing ICC-based colortransformations of rasterdata inside the driver 
including choosing source profile and rendering intent
- building queues with different setting
- exchange driversettings and profiles through different OS

The Turboprint people made a in my eyes a quite good job for ICC-ready 
printer drivers, which I have seen only in much more expensive 
RIP-solutions, or which I have missed in traditional printer drivers:
- vendor drivers (no CMYK profiling)
- Gutenprint (no handling of ICC-profiles)


But lets come back to the color architecture.

Lets imagine, that assigning ICC to driver settings is solved for the 
current driver. We now have to think about, to make it easy for the 
enduser to synchronize the colormanagement settings from his application 
to the print out.

If we look at the colormatch from the document colorspace to the 
monitor, it is pretty normal, that the application to handle the 
document is pulling the monitor profile from the system (or delivering 
rasterized data with a document (source-) profile to the system for output.

The monitor profile itself will be configured on systemlevel (Oraynos, 
Gnome ColorManager etc...).

If the printer profile should be configured in the driver, we need a 
mechanism, that the driver can tell the system, what is the current 
valid profile for the choosen driver setting.

In this case the color workflow from document to monitor and from 
document to printout would be pretty the same. An internal graphics 
engine, which can render the document from the document colorspace to 
raster output on the monitor, can also render the document to a raster 
print format.

If CUPS is between the document creating application and the printer 
driver, we need a possibility to transport the document colorspace 
through the CUPS file:
- If rasterized data are transported, this could be done through TOFF or 
JPG with embedded ICC profile
- I PDF data are transported, the PDF output intent is used.

This leads to following places where ICC-profiles are configured:

System:
- monitor profile
- RGB-source-profile (sRGB) for non colormanagement aware applications

Colormanagement aware application:
- Document colorspace (RGB and/or CMYK if necessary)

Printer driver
- Driver setting specific ICC profiles


Is this something we can agree on ?

best regards
Jan-Peter




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