[Scribus] CMYK -> RGB strikes again

Tino Schwarze scribus.lists
Mon Feb 21 13:52:18 CET 2005


Hi David,

On Mon, Feb 21, 2005 at 11:01:53PM +1030, David Purton wrote:

> > > > I've put up a web page describing my CMYK-RGB issues and illustrating
> > > > them with pictures.
> > > > 
> > > > Anybody with hands-on CMYK experience, please have a look at
> > > > 
> > > >   http://www.tisc.de/cmyktest/
> > > > 
> > > > It all boils down to "how do I convert sRGB images to CMYK correctly?".
> > > 
> > > You can try using my patch for Scribus 1.2.1. (unless you already have)
> > 
> > I already patched my 1.2.2cvs (some two weeks old) with your patch - the
> > files on the page were created with this version.
> 
> Really? I can't reproduce your behaviour.
> 
> This could be because there are yet more bugs in my patch ;) So let us
> see if we can track down what is wrong:
> 
> Firstly, your initial conversion to CMYK. This looks exactly as expected.
[...]

> Now for your scribus stuff... This is going to seem like a dumb
> question, but are you *sure* that my patch is applied? I ask, becuase
> the output you get both for the PDF X/3 and the CMYK pdf looks like what
> I get from an unpatched Scribus 1.2.1.

Doh. I will check that this evening (don't have my laptop at work).

> Have a look in scribus/util.cpp. If the patch is applied, the first
> function you come to in this file will be be:
> 
> QImage LoadPict (QString fn, QString Prof, int rend, bool useEmbedded,
>         bool useProf, int requestType, int gsRes)

I'm sure I patched Scribus (I remember patch complaining about some
"HUNK xzy succeeded with offset abc"), I recompiled and did a "make
install", which should have copied everything over to /usr/local/bin
(which is whas "which scribus" returns).

> If not, then either you have the first version of my patch without image
> support or something went wrong and it wasn't correctly applied.

I'm pretty sure that I used the 0.2 version of your patch.

> This is what I get using your image and the ISOcoated profile you
> recommended (PDF exported for printer (CMYK):
> 
>         http://marshwiggle.net/scribus/tino.pdf
> 
> Both the sRGB and the CMYK look nearly identical for me, both on screen
> and in the CMYK pdf (When viewed in acroread 5.09, other pdf viewers are
> not so good, of course)

Thank you very much for your time, this looks very promising now. :-)

BTW: Will export from sRGB to CMYK be improved by your patch as well? It
might save me the hassle of converting everything to CMYK then!

Bye, Tino.

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