Bug#424404: PDF files are much larger with lmodern than with CM fonts
Norbert Preining wrote:
> On Mit, 16 Mai 2007, Thanh Han The wrote:
>> this is a feature/limitation/bug/<call-what-you-like> of
>> pdftex: it doesn't remove unused Subs entries (this is very
>> tricky and dangerous), but replaces them by a dummy one.
>
> Ok, this is what was my idea, too, that unused subs are included. Didn't
> know that they are replaced by empty stubs.
>
>> lmr10 has a very large number of subroutines (~550), while
>> cmr10 has only 3. Another factor is that t1 fonts are
>
> Ok, that makes it clear where the difference comes from. I guess that
> the ~550 empty stubs take up a considerable space.
This is interesting. AFAIK the authors of the LM fonts go to great length
to produce these subs in the first place. Obviously this reduces the size
of the Type1 font itself. But as it has such bad effects on the resulting
PDFs, one might consider asking them to change this.
>> encrypted and hence they cannot be compressed effectively,
>> so all these dummy entries didn't get much smaller after
>> compression and therefore the result is a much larger size.
>
> Any plans for changing this feature/limitation?
That Type1 fonts are encrypted is not a feature/limitation of pdftex but
part of the specification of Type1 fonts. One alternative might be using
Type1C fonts, as GhostScript's pdfwrite device does. This might also be a
work around for the bug reporter:
ps2pdf <in.pdf> <out.pdf>
<out.pdf> should be quite a bit smaller. It might even be that GS removes
the empty subs besides using the more efficient Type1C fonts.
cheerio
ralf
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