[scribus] Aliasing and color problems

[Tino Schwarze]

On Mon, Jul 21, 2008 at 10:05:01PM +0200, Fabien SK wrote:

> > You should check carefully in which format you deliver your photos -
> > CMYK is probably not the best option if you're trying to pretent to
> > deliver original photos - these are in RGB. Unfortunately, I don't speak
> > French, so I cannot check their page.
> 
> That's what I think the only thing I can do (well, I did not know that
> CMYK JPEG even exists!).
> 
> About the profile, they explain how to do it on this page. It may be in
> french, but the screenshots of Photoshop are in english :-)
> They propose to work in RGB, then to export to an image using their
> profile.
> 
> http://www.photoweb.fr/atelier/atelier_photo_36.asp

> For the moment, I plan to:
> 1) export everything to PDF with no compression
> 2) import from PDF to some image format, maybe PNG (hhmmmmm, this
> process looks stupid, but I'm not an expert and Gregory advised me not
> to export to image with Scribus)
> 3) convert to JPEG
> 4) upload images, receive book
> 
> I don't know if I should use the profile conversion at step 1 or 3...
> Both make sens to me (but I'm not very skilled).

Looking at the profile they provided, you shoud NOT export to CMYK. They
use an RGB profile. Looking at the page, I'd suggest the following:

1) work in Scribus using RGB colors with no profile (this should be
equivalent to working in sRGB profile or whatever your camera uses - do
you have a profile for your camera?)
2) export to "Screen" PDF (not "Printer" since that will create CMYK!)
you may use lossless compression at medium level to save some disk space

3) run through Ghostscript, export to tiff24nc, like this:
gsc -dNOPAUSE -dBATCH -sDEVICE=tiff24nc -sOutputFile=image-%03d.tif \
-rRESOLUTION -dGraphicsAlphaBits=4 -dTextAlphaBits=4 -dUseCropBox your.pdf
-> replace RESOLUTION by the DPI they want
-> generates image-001.tif, image-002.tif etc.
4) run resulting TIFFs through tifficc like this:
for f in image-*.tif ; do
  tifficc -i /usr/share/color/icc/sRGB.icc -o ~/Photoweb.icc -b -t0 -c2 $f ${f/image-/page-}
done

If you've got a profile for your camera, use that as input profile for
tifficc's -i option. 

5) Convert to JPEG like this:
for f in page-*.tif ; do
    convert "$f" -quality 95 "${f/.tif/.jpg}"
done

HTH,

Tino.

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