[Openicc] printer, driver, CUPS, PPD, printing GUI, ICC-profiles, colord, Oyranos, taxi....

[Michael Sweet]

[Keep in mind, everything that follows is part of IPP Everywhere and is not specific to CUPS]

On Jan 16, 2012, at 8:39 AM, Kai-Uwe Behrmann wrote:
> ...
> How does a CUPS clients provide custom output profiles to the printer?
> Along a IPP Job ticket?


The currently published draft for the IPP Job and Printer Extensions - Set 3 (JPS3) is available here:

	http://www.pwg.org/ipp

Printers can advertise a list of vendor or site-configured ICC color profiles in the printer-icc-profiles-supported attribute, which tells a client what profiles will be used by default when doing color transforms from non-device color spaces to the device color space for the job.  The client cannot specify which profile is used for a given job in the job ticket (see below).

Printers can also advertise a list of rendering intents (the usual ICC stuff plus relative BPC) so that the client knows how those profiles will be applied during printing.  The client can specify which of those intents to use for a given job in the job ticket.

These attributes allow the client to do soft-proofing (for example, in the print preview window/dialog of a client UI) and client-side color management (if you don't like the printer's CMS but do like its profiles).

If you want to use a custom profile (or if you are doing client-side color management), you just supply document data using a device colorspace (e.g. DeviceGray, DeviceRGB, DeviceCMYK, etc. for PDF or PostScript).

If you want the printer to automatically use a custom ICC profile, the client sends a request to the printer (Set-Printer-Attributes) with the updated list of printer-icc-profiles-supported values.  That list becomes available to all clients of that printer...

....

Please let me know if the model we are using in JPS3 is not sufficient (and specifically why) as soon as possible since we are trying to lock down the technical changes for JPS3 for a working group last call in the coming month...

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Michael Sweet, Senior Printing System Engineer, PWG Chair