[scribus] pdf file size once more

[William F. Maddock]

On Sat, 2012-04-28 at 22:07 -0400, John Ghormley KJ4UFG wrote:
> I know this is a much hashed topic and I am not complaining, but rather
> trying to understand the whys of if all.  I just submitted a 60 page
> magazine pdf file to my pre-press folks.  They used InDesign to create a
> press quality pdf for use in making negatives for the offset press.  (I
> know, I know, that's old technology for a magazine but that is not the
> issue here.)  The pdf file I wrote with Scribus was 527 mb in size.  That
> was a greyscale option as opposed to printer or web.  The file written
> using the printer option was 1.5 Gb in size.  Anyway, the file written for
> the negative processing which was all 60 of my black and while pages after
> imposition was 36mb.
> 
> The question is, of course, how can a 38 mb container hold all the data in
> a 527 mb container?  Does InDesign use some compression technique that
> Scribus does not?  If so, why not?  After all, an almost 14:1 compression
> ratio is significant!
> 
> But, there may be a better explanation.  I just wish I knew it.

John,

If you were on a Mac (at least using OSX 10.3; I don't know about later
versions), I could have you do a test that might be very revealing.
Using the OSX 10.3 printer interface it is possible to easily create PDF
files. If you don't dig in and check any of the further options, you'll
get a completely uncompressed PDF file. When the print dialog comes up,
where it says "Copies and Pages", change that to "Output Options". Below
that, select "Save as File", format PDF. After this is where the
revealing difference comes in. Where it says "Output Options" change it
to say, "Color Sync". That brings up two additional menus. The "Quartz
Filter" menu is where the difference lies. Under that menu you can
select the option "Reduce Filesize", which makes a very significant
difference.

Under Linux, I use a script that executes the following commandline:

"ps2pdf -dEmbedAllFonts=true -dUseFlateCompression=true -sPAPERSIZE=letter $1"

I run that script on a Postscript file, and, again, it makes a
significant difference in filesize.

Windows I cannot speak to, since I do not use it.

In conclusion, it is possible that either scribus does not provide (or,
more likely, you are entirely missing) an efficient compression option
in its PDF creation. This could make the most significant difference in
filesize. Limiting the embedded resolution of images can make a
difference, but running a compression algorithm over the entire output
will compress even reduced resolution images.