[Openicc] GoSoC 2011: CPD and target printing

Kai-Uwe Behrmann ku.b at gmx.de
Thu May 5 13:28:02 PDT 2011

Hello Alastair,

Am 05.05.11, 20:24 +0100 schrieb Alastair M. Robinson:
> On 05/05/11 16:32, Chris Murphy wrote:
>> If a single application cannot be produced to do this correctly and
>> reliably, we certainly have the very same problem with it in a CPD that
>> then all applications are subject to with no other (simple) means of
>> working around it. I think that's a problem.
> What strikes me is that if it's impossible to do pass-through-colour using 
> the CPD then our standalone target-printing application has to bypass 
> the CPD completely.

Oh, thats not our goal. In the scheme diagram [1] is shown how to get pass 
through with CPD following the PDF/X standard.
PDF objects can only be tagged with ICC profiles if no prematched 
data, this means a PDF without OutputIntent, is obtained.
By CPD honouring a OutputIntent it is easily possible to print without 
altering any colour profiles in the PDF. Then DeviceXXX will be preserved.

What would be possible by this scheme:
* cli tool to generate a finalised target PDF which prints in passthrough
* cli tool to convert a input image into a finalised target PDF
* a finalised target PDF is printed on the command line
* a finalised target PDF is sent to CPD
* the finalised target is created in a GUI app and printed to CUPS
* the finalised target is created in a GUI app and sent to CPD

I hope for all cli and GUI fans is some combination at least possible. It 
will not necessarily mean we have Linux converted instantly and osX and 
Windows too.

As we are in the GSoC thread, I would wish Joseph comes to a working 
set of command line tools. If a GUI could be updated to use the scheme 
that would be great. But lets see how trivial or complicated the project 
will be. Polishing for robustness is more vital than bells and whistles in 
the first place.

kind regards
Kai-Uwe Behrmann
developing for colour management 
www.behrmann.name + www.oyranos.org

[1] http://www.oyranos.org/wiki/index.php?title=Device_Settings#CUPS

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