[Scribus] cmyk workflow

[Gustavo Homem]

Hi again,

> > What's the difference in the CMYK conversion of an imported RGB picture
> > between CM=off and CM=on (with the default settings)?
>
> I don't know wich CM settings are used when scribus is in default mode
> (CM is off) - does this sound confusing?
> Simply any color conversion is anyhow managed and done by conversion
> tables or/and algorithms.

I'd like to understand how those two cases compare. See below for the reason.

Maybe some developper can help to clarify this?

>
> If you switch CM on first think different is that you are able to use
> the input profile setting in the pdf output dialog.
> (and don't use what is hidden and unknown).
> Another is that you are able to set in and output profiles in your
> overall and document settings.
> With CM on you can use the Print Preview (though I think it's broken
> and does not display what it should).
>
> Concluding this, if you enable CM your enabling yourself to let scribus
> provide more correct color conversions - if set properly and as long as
> scrbus has no bug here .... or there.

I understand the principle. However, the workflow I am close to, works like 
this:

1- Photographer takes pictures (RGB JPEG)
2- Pictures are edited for color, brightness, etc on PS and saved again (RGB 
JPEG)
3- Another guy opens the pictures on PS, changes some more parameters, crops, 
cuts and exports from PS as a CMYK EPS using the default PS profile. He also 
saves the CMYK PSD.

4a - CMYK EPS is imported to QXP, which then generates Postscript, then 
converted to PDF via extra tools
4b - CMYK PSD is imported to Scribus which generates directly PDF

5 - PDFs from 4a and 4b look exactly the same

There are no colour profiles involved besides the PS default. The rest comes 
from intuition.

So, I'd like to know how to have this RGB -> CMYK conversion working well 
enough to take PS out of the equation (step 3), but without complicating the 
process.

>
> > How do both scenarios compare to the default photoshop RGB-> CMYK
> > conversion?
>
> Different Methods. PS allows to use different CMMs
> (ColorMatchingModules) and provides nearly correct previews on
> calibrated monitors.
> photoshop is expensive. You cannot change colormodes in photoshop
> without CM.
>
> Does this answer your questions?

Well, not completely.

See also my email about recommended workflows for Scribus.

BR
Gustavo


> Jon
>
> > Thanks
> > Gustavo
> >
> >> More generic but possibly more sufficient settings:
> >>
> >> set profile RGB-Pictures to RGB (ECI-RGB or sRGB or Generic)
> >> set profile CMYK-Pictures to CMYK (ISO-coated or ISO-uncoated or
> >> Generic)
> >> set monitor to (ECI-RGB or sRGB or Generic)
> >> set printer to (ISO-coated or ISO-uncoated or Generic)
> >>
> >> set rendering intents
> >> monitor to relative colormetric
> >> printer to photographic or perceptive
> >>
> >> check compensate black
> >>
> >> You may obtain the mentionend profiles at www.eci.org, for better
> >> results you should install them.
> >>
> >> Using CMM does not mean you wont run into any problems with colors
> >> wich
> >> cannot be converted.
> >> But it helps a lot.
> >>
> >> And, no, I am afraid I cannot help you with installing CMM under Linux
> >> or Windows.
> >>
> >> Another way around is to change the colors in your png (in Gimp) to
> >> something which in your opinion
> >> might be printable. And reimport these files.
> >>
> >> Jon
> >>
> >>> Am I doing something wrong here?
> >>>
> >>> I ought to have it sent and proofed today, so every help is
> >>> appreciated :-)
> >>>
> >>> Best regards
> >>> Axel Bojer
> >>> _______________________________________________
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> >>
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> >
> > --
> > Angulo S?lido - Tecnologias de Informa??o
> > http://angulosolido.pt
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-- 
Angulo S?lido - Tecnologias de Informa??o
http://angulosolido.pt