[scribus] TIFF problem and 1-bit images

[William F. Maddock]

-----Original Message-----
>From: john Culleton <John at wexfordpress.com>
>Sent: Jul 8, 2012 9:04 AM
>To: scribus at lists.scribus.net
>Subject: Re: [scribus] TIFF problem and 1-bit images
>
>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

Wouldn't it be better to import line art in a vector format, anyway? It might be laborious, but it should be possible to trace the line art into a vector format. That should save an awful lot of file size right there, and get better output to boot.