You can try to "restore" your PDF file using pdftk using Ghostscript (but use the latest version, for example, 9.05). In many cases, Ghostscript will be able to combine many subsets of fonts into several.
The command will look like this:
gswin32c.exe ^ -o output.pdf ^ -sDEVICE=pdfwrite ^ -dPDFSETTINGS=/prepress ^ input.pdf
Check with
pdffonts.exe output.pdf pdffonts.exe input.pdf
the number of instances of different subsets of fonts in each file ( pdffonts.exe available here as part of a small command-line tool package ).
But do not complain about the "slow speed" of this process. Ghostscript fully interprets all input PDF files to accomplish its task, and concatenating pdftk files is a much simpler process ...
Update:
Instead of pdftk you can use Ghostscript to merge your input PDF files. This could have avoided the problem that you saw using a posteriori Ghostscript to “repair” your pdftk files. Note that this will be much slower than the "silent" pdftk merge. However, you may like the results, especially with regard to font handling and file size.
This would be a possible command:
gswin32c.exe ^ -o output.pdf ^ -sDEVICE=pdfwrite ^ -dPDFSETTINGS=/prepress ^ input.pdf
You can add additional options to the Ghostscript CLI for finer control over the merge and optimization process.
In the end, you have to decide between extremes:
- 'Fast'
pdftk creating large output files, vs. - "Slow"
gswin32c.exe (Ghostscript) creating files with a clear output file.
I would be interested if you would publish some results (runtime and resulting file sizes) for both methods for several merge processes ...
Update 2: Sorry, my previous version contains a typo.
This is not -sPDFSETTINGS=... , but it should be -dPDFSETTINGS=... ( d instead of s).
Update 3:
Since your source files are Excel worksheets created from templates (which usually don't use many different fonts), you can try the trick to make sure that Ghostscript has all the necessary glyphs for the fonts used in all, -be-merged-later PDFs:
- For each font and face (standard, italics, bold, bold, italics) add a table cell to the template sheet in the upper left corner of the print area. A.
- Fill this table cell with all printed and punctuation characters from the ASCII alphabet:
0123456789 , ABCD...XYZ , abc...xyz :-_;°%&$§")({}[] , etc. - Make the cell (and font) as small as you want or want, so as not to interfere with your layout. Use white to format the characters in the cell (so that they look invisible in the final PDF file).
This method, we hope, will make sure that each of your PDF files uses the same glyph subset, which then avoids the problems that you observed when merging files with Ghostscript. (Note that if you use fe Arial and Arial-Italic, you need to create 2 such cells: one is formatted with the standard Arial font, the other with italics.)