[cups] where to store device-specific ICC profiles

[Helge Blischke]

> Am 02.12.2016 um 13:35 schrieb Axel Braun <axel.braun at gmx.de>:
> 
> Hello Helge
> 
> Am Freitag, 2. Dezember 2016, 11:24:16 CET schrieb Helge Blicke:
>>> in order to improve the color printing of a Brother laser printer I got me
>>> a ICC profile.
>>> Searching through the different explanaations I found that icc profiles
>>> are
>>> stored under /usr/share/color/icc/ , and should be available for all
>>> applications that can make use of color profiles.
>>> In this directory are already a bunch of icc/icm files.
>>> If I want to use the newly created icm file just for one of the defined
>>> printers on my system, where do I have to place it?
>>> I'm running on openSUSE Leap 42.2 with CUPS 1.7.5
> 
>> To set up this profile for exclusive use
>> for the said printer, look into the cups
>> PPD extensional for how to use the
>> *cupsICCProfile keywords.
>> I think the cups-filters package *does* support them (if not ask me for a
>> suitable workaround).
> 
> Yes, had a look into this. But was not sure about it.
> In general I can place a profile under /usr/share/cups/profiles/ - But I 
> understand that this is used for all Cups devices.
> 
> If I want the profile only in one printer, I need to modify the .ppd file for 
> it, correct?
> So I copied the ppd with a new name, and added a line 
> 
> *%=== Color Management ================================
> *cupsICCProfile ../Default: "/etc/cups/profile/
> BrotherMFC9340CDW_Kopierpapier.icm"
> 
> When printing a test page from GIMP, I get the tree option
> Color Mode = none / normal / vivid
> 
> should I use 'none', as color mode is now managed by the profile?
> 
> Thanks
> Axel

Axel,

it seems that the cups-filters package only supports cue *cupsICCProfile keyword and its companions only for
the image filters (image/xxx to whatever) and the filters that convert PDF or PostScript to one of the
raster formats supported by cups.

So please tell what printer language your brother printer is configured to use.
In case of br script 3 (brother’s PostScript level 3 emulation) it may be that this directly supports
ICC profiles somehow – but I couldn’t get any specification which could conform or disprove that.

In any case, in a PostScript- or PDF-oriented workflow the use of littlecms (lcms2) provides utilities
to convert ICC profiles to PostScript CRDs, which should work with every at least level 2 PS interpreter
(though the true ICC fans think CRDs are really a devil’s spawn).

And yes, it would work to use ghostscript (a version >= 9.0) to convert PostScript /PDF to PostScript / PDF 
with considering the ICC profiles in a „professional“ way (by using an additional filter, of course).

Last, a remark to the GIMP: GIMP’s printing plugin is, as far as I know, completely independent from CUPS,
so I don’t think it will honor the PPD keywords in question.

Helge