[pdftex] Producing and optimizing PDF-1.2

Cosmin Truta cosmin at cs.toronto.edu
Wed Oct 3 21:24:37 CEST 2001

Hello, pdfTeX gurus,

I am sorry I don't know much about the PDF internals. This is why I would
like to ask you a few questions.

I wish to produce PDF compatible with Acrobat 3 (i.e. PDF-1.2). I noticed
that the pdfTeX versions later than 0.14a produce PDF-1.3 by default, and
I am using pdfTeX-0.14f  under MiKTeX-2.0.
Is it any way to convince newer versions of pdfTeX to produce PDF-1.2,
such as the "-dCompatibilityLevel=1.2" switch in Ghostscript, or the
"/CompatibilityLevel 1.2" switch in Distiller?
- or: is the PDF-1.3 produced by my pdfTeX already compatible with
Acrobat 3? (e.g. is it safe to replace "PDF-1.3" with "PDF-1.2" manually
in the output?)
- or: is there any way to "distill" PDF-1.3 and produce valid PDF-1.2,
without losing hyperlinks or bookmarks?
- ultimately, do I need to downgrade to pdfTeX-0.14a if I want to obtain

Another question is about the "optimized" field of a PDF file. I believe
this kind of optimization is different than the zlib compression level,
because even if I set \pdfcompresslevel to 9, the reader shows me
"Optimized: No". Does this optimization refer to the internal organization
of the PDF structures, so that the file takes less memory or disk space,
or perhaps can be printed faster? Can I set the pdfTeX optimization
flag; if yes, how?

At the end, I would like to remark that the output of "dvips -Ppdf -G0"
followed by Distiller is smaller than the output of pdfTeX, even if I
didn't use hyperref. On the other hand, pdfTeX gives a smaller output than
the same postscript distilled with ps2pdf/Ghostscript. Distiller produces
an "optimized" PDF, while Ghostscript produces a "non-optimized" one. The
compression level 9 was used in all cases.
Does this mean that, at this issue, the Distiller is better than pdfTeX,
which is better than Ghostscript?

Thank you very much for giving pdfTeX to the community!

Best regards,

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