[Scribus] "Nice" PDF

[Wolfgang Dobler]

[I cannot find the thread on this, so I have to start a new one]

I think I have found a way to convert Scribus' (printing-press oriented)
PDF into `nice' (more Web-oriented) PDF.
Here's the story, plus a few questions:


My wife edits a newsletter
(http://www.calgarymulticulturalcentre.com/newsletter.htm) that is mostly
distributed via e-mail and the web (but some volume is also printed
black-and-white at an inexpensive print shop). After her Windoze machine
died and she could no longer use PageMaker and Distiller, I convinced her
to use Scribus on Linux, and apart from her occasionally cursing myself
for this, things works fine (she likes the CVS version much better than
1.2).

Being sent out via e-mail, the newsletter _must_ be below ~ 1 MB,
desirably even smaller. Since the Scribus options for minimizing the size
(subsetting fonts and downsampling images) did not meet that requirement
(I'd need to try again to give figures), I looked for a route to
PostScript and back to PDF that would give better compression, and the
following does a surprisingly good job:

  1. Export as PDF, embedding all fonts, no font subsetting, no image
     subsampling
     --> newsletter_scribus.pdf [~2.8 MB]
  2. Convert to PS using `pdftops -level3' (Acroread 7's PS export will
     _not_work)
     --> newsletter.ps [huge]
  3. Convert back to PDF using ghostscript (subsetting fonts, subsampling
     images; this must be ghostscript 8.x or later)
     --> newsletter_compact.pdf [~500 kB]

As you see, the resulting PDF is more than 5 times smaller.


And now for the mysterious part: The new PDF file is not only smaller, but
it is `nicer' (for on-screen reading) in three aspects:

(i) In Acroread 7 (the buggy one, I don't have any other around for
  comparing) on Linux, the text appears not to be antialiased for the old
  PDF, but is perfectly so for the new one.
  Xpdf shows both fine (and identical as far as I can tell).
  Gv/ghostscript hangs while antialiasing the old file, but shows the new
  file fine.
(ii) Text marking and searching in the old file works not too well in
  Acroread (with lots of gaps in marked text), and practically not at all
  in Xpdf. It works perfect for the new file in both applications.
(iii) The picture is shown far too dark in Acroread for the old file, but
  fine for the new file. Xpdf once again shows identical results for both.


You can see Acroread's output of both files at
  http://www.capca.ucalgary.ca/~wdobler/tmp/Scribus/

Can anybody explain this to me? I attach some vague ideas, but I find this
behaviour really striking.

  Point (i) could be the switched-off font hinting in Scribus' PDF that
    was mentioned before. But how on Earth can pdftohtml + gs reconstruct
    the hinting information?

  Point (ii) sounds like it is caused by Scribus placing separate
    characters into the PDF, rather than whole words -- and gs
    reassembling the words very efficiently.

  Point (iii) could have to do with the fact (I am quoting out of my head)
    that Acroread never touches the CMYK values, while other viewers apply
    colour profiles (or such).

Any rebuttal/confirmation of these thoughts and further enlightenment are
welcome.


W o l f g a n g


PS: If anybody is willing to run the resulting file through a PDF checker, you
    can try the latest newsletter at
      http://www.calgarymulticulturalcentre.com/CC_January_2006.pdf

PPS: I guess I should put this into a Wiki page, it could be useful for
    many others.