[Openicc] printing GUI vs. printerdriver, LINUX colorinfrastructure

[Leonard Rosenthol]

At 08:33 AM 4/16/2005, Jan-Peter Homann wrote:
>The printerdriver is driving the printer directly.

         As was pointed out by someone else - there are two types of 
"printer drivers" in existance today.  One that converts from application 
API calls to some form of page description language (PDL) (eg. Postscript 
or PDF) - this is what GnomePrint, the KDE print manager, the Adobe PS 
driver on Windows, etc. do.   The second is responsible for the hardware 
connectivity to the printer.

         In our discussions, the latter is not important (we don't care how 
the bytes get to the device) - only the former is...


>  Mainly this is the rasterization for the printed dots, some kind of 
> colormanagement

         Conversion of application API calls and/or PDL to a raster image 
are done either by a RIP OR in the actual printing device (eg. Postscript 
printer).

         Many RIPs have integrated color management.  This is esp. 
important in RIPs for languages like Postscript and PDF - where (as has 
been noted before) individual objects may be described in different 
colorspaces.  The "flattening" of the colorspaces needs to take place in 
this process OR potentially somewhere up the workflow with native language 
processing tools (eg. a PDF/X compliance system).


>As described in mails before, we have four main possibilities to transform 
>color for printing:
>1. colormanagement in the application
>2. colormanagement as CUPS-filter
>3. colormanagement with CSA/CRD in the PostScript-RIP
>4. colormanagement in the printerdriver

         True, though I doubt #4 actually happens (assuming you mean driver 
as hardware controller). If you mean the app->PDL component, then yes, that 
can include color management.


>In the printing GUI, the user should specify, which way of colormanagement 
>he is using.

         I don't see how that is possible...


Leonard

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Leonard Rosenthol                            <mailto:leonardr at pdfsages.com>
Chief Technical Officer                      <http://www.pdfsages.com>
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