[Openicc] LINUX, Gutenprint / CUPS / Color policies

[Michael Sweet]

Jan-Peter Homann wrote:
> Hello Robert, hello List
> Even if I not understand every detail about the CUPS discussion, there 
> are some points, which are very important for building a transparent 
> color-infrastructure.
> 
> First point is, where is the colortransformtion from document-colorspace 
> to printer-colorspace done.
> 
> In strongly recommend to do this in the printer-driver and not in the 
> application, in the RIP or in CUPS. This should be part of the 
> printer-driver.

This actually isn't what I would recommend - PDF documents, in
particular, can have images and colors in many different colorspaces
using many different profiles - at some point you need a common
colorspace with the printer driver so that the color info is
accurately conveyed.

The whole purpose of the CUPS raster driver interface is to *simplify*
the color management interface, such that a RIP can provide the most
convenient color data for the driver, not force color management on
it.

Nothing in the CUPS driver interface prevents a driver from doing its
own color management (at whatever level), but the RIP has to deal with
the multiple input colorspace scenario regardless of the driver's
abilities.

> ...
> 3. Path-through of the document-colorspace to the printer-driver

That won't work, simply because most printers are dumb raster devices
and the drivers need raster data in a single colorspace, not a mix.

-- 
______________________________________________________________________
Michael Sweet, Easy Software Products           mike at easysw dot com
Internet Printing and Publishing Software        http://www.easysw.com