[Openicc] Actually getting color managed printing to work

Michael Sweet msweet at apple.com
Sat Jan 28 19:51:44 PST 2012


Edmund,

CUPS knows about ICC profiles, in as much as the filters support them and cupsd registers the ones listed in the PPD file, but it doesn't know about the calibration data used internally by the driver.

So if you want access to the levels/curves in Gutenprint (say, to use a custom set of dither parameters for a particular media type) then you'll need to pull the XML data from the profile used.


On Jan 28, 2012, at 1:17 PM, edmund ronald wrote:

> Richard, 
> 
>  I think the profile stuff happens in CUPS upstream from Gutenprint - this is a raster driver which doesn't know about colorspaces. So Gutenprint won't be reading profiles. Robert may have something different to say. 
> 
>  My belief, confirmed by today's phone conversations is that CUPS knows a lot about profiles though, and performs profile conversions on input data when asked nicely. 
> 
>  More pertinently , if Gutenprint writes XML (dumps its presets), it is probably being called to print a target which means that the image is DeviceRGB o DeviceCMYK -no input profilein sight and indeed none available yet. 
> 
>  Of course you could want Gutenprint to embed the written XML in some available profile, but that is a long time after the print has dried and been measured, so you have no reason to print again, so why ask Gutenprint? 
> 
> Edmund
> 
> 
> On Sat, Jan 28, 2012 at 10:04 PM, Richard Hughes <hughsient at gmail.com> wrote:
> On 28 January 2012 19:56, edmund ronald <edmundronald at gmail.com> wrote:
> > So, my suggestion would be that you write the code to embed and to unembed
> > the XML in profiles, and you task us structure the XML itself in ways which
> > would help you, but let  us momentarily define a way we can work now with
> > "naked" XML and no superstructure when no profiles are involved.
> 
> Sounds like a fair deal. Do you want a library to use, or just provide
> a couple of lcms2 example snippets that can be licenced as
> BSD/GPL/whatever for copy/pasting? Maybe a command line utility might
> be easier. The cd-fix-profile utility already allows you to add random
> metadata to profiles, although a simpler utility might be better. Let
> me know what you would prefer.
> 
> Richard.
> 
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_________________________________________________________
Michael Sweet, Senior Printing System Engineer, PWG Chair

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