[Printing-architecture] Make use of extended color spaces on IPP printers

Michael Sweet msweet at msweet.org
Tue Jun 1 00:54:20 UTC 2021


> On May 31, 2021, at 3:38 PM, Till Kamppeter <till.kamppeter at gmail.com> wrote:
> On 31/05/2021 20:13, Michael Sweet wrote:
>> Till,
>>> On May 31, 2021, at 11:03 AM, Till Kamppeter <till.kamppeter at gmail.com> wrote:
>>> ...
>>> Do you know which Linux applications generate correct PDF files?
>> Sorry, I did some quick testing and wasn't able to find a single Linux application that does things properly...  Maybe we can fix that...
> How would you fix that in CUPS/cups-filters?

There isn't any way to fix it in CUPS/cups-filters.

> For me it looks like a bug in the PDF generators in the applications, meaning that one has to report this for every PDF generator. Cairo probably covers a lot of applications, but for example specialized photo applications (darktable, RawTherapee, ...) probably have their own PDF generators, and they all have this bug.

So we file bugs and provide a pointer to sample code that supports calibrated and ICC color spaces.

> It is really a bug as the applications send PDF files where the printing system cannot determine which is the color space actually used and so it cannot correctly reproduce the colors on a printer and use the most suitable of the color spaces which the printer offers.

At this point CUPS needs to treat the output color space as the device color space.  Typically sRGB, sometimes AdobeRGB, less commonly a different device RGB/CMYK color space.

Michael Sweet

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