[Openicc] Printing targets: App or driver ? Profiling RGB or CMYK

[Jan-Peter Homann]

Hello Edmund and all,
I support, that profiling for Gutenprint should start based on the 
avilable RGB Gutenprint setups.
May questions are about possibilities to allow an easier CMYK based 
profiling for Gutenprint in future (no need to prioritize).

The main idea behind:
Gutenprint must handle total inklimit and blackgeneration if it can be 
driven with RGB-data.
If we have working Gutenprint settings, we may could use the information 
to configure the Argyll profiler for CMYK based profiling and may be 
also the Argyll target generation (may be necessary for media ink 
combinations with very low total ink limit), .
In this case, we need special targets, which contain only patches under 
the ink-limit.

But as i said, this needs no priorization and is more interesting to 
color geeks, which e.g. want to compare the results for RGB and CMYK 
based profiling for the same media settings.

Best regards
Jan-Peter

Am 17.05.11 16:21, schrieb edmund ronald:
> I don't understand anymore where this is going. Yes Gutenprint can be 
> profiled in CMYK. There are no technical issues, I have done it, any 
> color consultant can do it. No, this cannot be done easily with tools 
> available to hobbyists, and with the current Linux software driving 
> GP, and the quality one gets with the built-in RGB==>CMYK  I don't 
> think there is an immediate need to prioritize this route.
>
> Edmund
>
>
> On Tue, May 17, 2011 at 2:59 PM, Robert Krawitz <rlk at alum.mit.edu 
> <mailto:rlk at alum.mit.edu>> wrote:
>
>     On Tue, 17 May 2011 10:03:26 +0200, Jan-Peter Homann wrote:
>     > Hi Alastair,
>     > You made a good point. For a smooth step forward, with current
>     available tools and settings (Argyll / Gutenprint), you correct,
>     that profiling in RGB based on a good Gutenprint RGB->CMYK Setting
>     is easier for crowd profiling, which is quite important for the
>     next months.
>     >
>     > Question to Robert Krawitz:
>     > There are a lot of testet Gutenprint settings available, which
>     include the Gutenprint specific RGB->CMYK conversion.
>     > - Is it possible to create a Gutenprint "CMYK-only" setting by
>     just deactivating the RGB->CMYK conversion ?
>
>     "Deactivate the RGB->CMYK conversion"?  I don't understand.  If one
>     were to do that, they would get RGB output (or perhaps CMY, depending
>     upon how it's defined; Gutenprint does offer CMY output).
>
>     Based on the rest of this, are you really asking "is it possible to
>     determine the internal settings Gutenprint is actually using"?
>
>     > - Is it possible to to read easily following parameters from the
>     deactivated RGB->CMYK conversion:
>     >      - Black generation settings ?
>     >      - Total ink limit ?
>
>     No, not at present.  I can see API changes that would make it
>     possible.
>
>     > For stepping into CMYK profiling, this could lead to following
>     workflow
>     > - read the Gutenprint settings black geneartion and ink-limit
>     for an tested setting
>     > - deactivate the Gutenprint RGB-CMYK conversion
>     > - Print the testchart
>     > - generate profile with similar settings for black generation
>     and ink-limit
>     >
>     > Question to Graeme Gill:
>     > Some Ink / Media Combinations need heavy total ink limits. Is it
>     possible with Argyll to create CMYK-testcharts which are
>     alraedyoptimize for an ink limit and black generation ?
>
>


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