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Re: Permitting PDF and Postscript (was: RE: Baby Steps (was RE: Alternative formats for IDs))

2006-01-05 14:46:02
In message <266A4D6A4BC4722364791F3A(_at_)p3(_dot_)JCK(_dot_)COM>, John C 
Klensin writes:

--On Thursday, 05 January, 2006 12:46 -0500 "Gray, Eric"
<Eric(_dot_)Gray(_at_)marconi(_dot_)com> wrote:


     I believe - for the record - that Post-Script is also

It is indeed.  And it, as well as PDF, are allowed in RFCs (see
earlier note).

As others have noted, an ASCII form is still required.  I
consider that a feature and, for various worst cases,
futureproofing, but some others do not.

And, as yet others have noted, it would be wise for us to get
very specific about versioning and permitted feature-sets for
PDF.  It is arguably even more important to get specific about
versions and feature sets for PS although my own personal
opinion is that, given PDF, Postscript has about outlived its
usefulness as a separate posting format.  YMMD, of course, and
this thread on the IETF list is probably not the optimal way to
address that question in any event.

Producing good, portable PDF isn't obvious.  I just added the following 
text to a Call for Papers of a conference I'm chairing, based on many 
sad experiences trying to read random PDF files submitted by others:

        PDF users should use "Type 1" fonts instead of "Type 3", and 
        should "Embed" and "Subset" all fonts.  You can find 
        instructions on how to do this at

Among the problems I've encountered have been version skew, missing 
fonts (especially Asian language fonts that are frequently not 
installed elsewhere), fuzzy text from LaTeX users who are generating 
bitmap fonts, ligatures getting changed into weird characters, and more.

When I sent the PDF for the second edition of my book to the publisher, 
I had to use these options to dvips:

        -P pdf -G0 


        -dMaxSubsetPct=100 -dCompatibilityLevel=1.3 -dSubsetFonts=true 

for ps2pdf.  (I've left out the resolution.)  I should note that it 
didn't work, either -- but if I sent them the PS, they could convert it 
to PDF.  We never did figure out that problem....

                --Steven M. Bellovin,

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