[scribus] TIFF problem and 1-bit images

[john Culleton]

On Sun, 8 Jul 2012 14:55:14 +0300
Jussi Pakkanen <jpakkane at gmail.com> wrote:

> Hi
> 
> I'm helping a friend put together a comic book. We have separated
> colors from lines and saved each to their own files. The lines are 1
> bit TIFFs generated with Photoshop. Some of those TIFF files crash
> Scribus (relevant bug: http://bugs.scribus.net/view.php?id=10854)
> 
> Debugging the issue on my machine where the images can be loaded
> produced some strange results.
> 
> A test page with one color image and the corresponding line image on
> top of it create a 11 MB PDF.
> 
> If I convert the line image to PNG using either ImageMagick or Gimp,
> Scribus produces a 21 MB PDF file.
> 
> More strangely, for the tiff image, Scribus says that its color space
> is grayscale.
> 
> For both of the PNG images, Scribus claims they are RGB.
> 
> ImageMagick's identify binary claims that they have only 1 bit color
> channels.
> 
> All source images are roughly the same size (~0.5 MB). Why do the PNG
> files produce so much bigger PDFs?
> 
> It is extremely important that the 1 bit line images do not get
> rasterized during printing. Currently they are set to multiply mode.
> Is that the correct setting?
> 
> Is there a way to inspect the resulting PDF file to ensure that the
> line art images in it are 1 bit? The fact that Scribus says that they
> are RGB makes me a bit uneasy.
> 
> Thanks a lot for any info
> 
> ___

Well perhaps they are RGB. When you use imagemagick do you change the
colorspace to cmyk? I would also try saving the files as png
directly from Gimp, and use maximum compression. If you use the
correct ICC profile in scribus they will go to cmyk anyhow. So my
flow would be:
Gimp->png->Scribus->save for print with cmyk profile.

The png files are big because they are not lossy. But it is
possible to compress them when they are created. 

John Culleton
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