Re: [Printing-architecture] Bye-Bye colord - OR - Poll ICC profiles via IPP for soft proofing

Sebastian,

> On Aug 23, 2022, at 7:48 AM, Sebastian Wick <[email protected]> wrote:
> ...
> When you say associate a profile with a print queue, what exactly does
> that mean?

I mean "when doing a soft-proof of this document for this printer, use this profile". It could just be implemented as a history/most recently used chooser in the soft-proofing UI, where there can be a "Printer Profile" submenu/section (populated from "printer-icc-profiles") and "Other..." to pick a file from disk.

> That all images in the queue have color characteristics
> described by that profile?

No, given the current CUPS print pipeline we are best served by sticking with standard color spaces (sRGB, sGray, and AdobeRGB) and only using printer profiles for soft-proofing.  Longer term we should probably have CUPS use printer-specific profiles (as supplied by the printer) to produce DeviceK/RGB/CMYK raster data for non-PDF printers, but since the number of printers supporting that is very small we shouldn't try to optimize that case yet.

> That the printer converts the images which
> are tagged by possibly other profiles to that profile? Can you associate
> any profile with a print queue or only ones the printer supports? Do all
> printers support certain color spaces?

So IPP Everywhere and AirPrint require sRGB/sGray raster support, and most photo printers also support AdobeRGB.  A few large format (raster) printers (currently) support printer-icc-profiles, and any PDF printer will support embedded ICC source profiles that get chained with the internal ICC profiles to produce correct DeviceN color on the printer itself.

> Is this kind of information documented somewhere?

Yes, in the IPP Everywhere specification:

	https://www.pwg.org/ipp/everywhere.html

________________________
Michael Sweet

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