[cups] where to store device-specific ICC profiles

[Axel Braun]

Hello Helge,

Am Freitag, 2. Dezember 2016, 16:35:35 CET schrieb 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?
> > 
> 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.

From what I can find in the ppd file it is Postscript level3, as you expected

*%==== Basic Device Capabilities =============
*LanguageLevel: "3"
*ColorDevice: True
*DefaultColorSpace: RGB
*FileSystem: False
*Throughput: "17"
*VariablePaperSize: False
*TTRasterizer: Type42
*FreeVM: "1700000"

And:
*cupsFilter: "application/vnd.cups-postscript 0 brother_lpdwrapper_mfc9340cdw"

> 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).

I can at least tell you that ghostscript 9.15 is installed, for the rest I 
know too less of color handling to understand.
As Apple uses the same print technology I has hoping that there is an 'easy' 
way to apply color profiles to a printer....

> 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.

Good point, so it makes sense to print from any other format, e.g. PDF.

Thanks
Axel