[Scribus] colours in pdf

[Terence Chan]

I have been using scribus with colour management enabled. My
original post was really about the apparent discrepancy between
the appearance of the images in scribus and in pdf even after
applying the appropriate icc profiles; everything in scribus
(including the print preview) looked fine but not in pdf/acroread.
Having experimented a bit more, I've found a solution of sorts,
namely I need to export to PDF/X-3 and the pdf file then
looks exactly the same in acroread as in scribus, whereas PDF 1.x
won't work. But the thing is, if I use another pdf viewer, such
as xpdf, the images look fine on screen even in PDF 1.x - why is
that?

For information, my system setup is as follows:

Fedora Linux Core 5
Scribus 1.3.3.4
Acrobat 7.0.8 for Linux
lprof 1.11.4.1
lcms 1.15

Terence

On Mon, 6 Nov 2006, Craig Ringer wrote:

> Terence Chan wrote:
> > Thanks to all those who replied to my previous post about colour
> > management. I've just about got the hang of it now, apart from some
> > fine tuning. My one remaining concern is that once I've exported
> > to a pdf file, the colours look nothing like the scribus original in the
> > Acrobat reader acoread.
>
> How does it compare to the print preview in Scribus? How about the
> on-page rendering in Scribus when the colour management preview is enabled?
>
> > Indeed even B&W images for which colour
> > management isn't an issue
>
> Isn't it?
>
> Pure B&W perhaps, but do you mean B&W or greyscale? AFAIK colour
> management is an issue for greyscale images, as dot gain can change
> their reproduction significantly. I don't think ink weight limits are a
> factor in 1-channel images, so it'd pretty much be down to compensating
> for dot gain. Come to think of it, it's probably an issue for pure B&W
> images as well, but I'm not sure since I *never* deal with them.
>
> So ... exactly what kind of image are you speaking of? What colour
> format is it in? RGB? Greyscale? 1-bit B&W? This can matter quite a lot.
>
> > appear quite differently in acroread. Is
> > this just a problem with the way acroread displays images, or do I have
> > to apply the CMYK profiles if I want to provide a pdf file to a
> > professional printer?
>
> Well, you haven't said (in this message at least) how you're exporting
> currently. Please give details such as:
>
> 	- Scribus version
> 	- Platform, OS and version (eg "Fedora Core 6 on an Athlon 64")
> 	- PDF viewer and version (eg "Adobe Reader 7 on Linux")
> 	- Whether colour management is enabled in Scribus and if so
> 	  which profiles you are using.
>
> and once you've provided that information we'll see about giving you
> some useful answers.
>
> If I *assume* that you are currently _not_ using colour management in
> Scribus (given your question about whether you need to use a profile),
> then I would expect you to see colour issues in your exported document.
> Unprofiled RGB->CMYK conversions are iffy at best, and terrible if you
> have images that are outside the CMYK gamut. A colour profile will not
> magically make it all work (especially with out-of-gamut issues) but
> will definitely help get a better conversion.
>
> Remember that RGB colour != CMYK colour. Sometimes shifts are inevitable
> simply because there are colours that can be represented in RGB but not
> CMYK. Also, because of ink weight limits on the press, compensation for
> dot gain, etc your images may be intentionally adjusted to get a better
> print reproduction even though it won't look as similar on screen.
>
> To say whether this is what is happening, or if something is going
> wrong, we'll need details like I asked for above. Samples of your PDF
> output and your original images would also be extremely helpful in
> eliminating the guesswork from any answers someone on the list might
> give you. We're not psychic you know ;-)
>
> --
> Craig Ringer
>
>