Re: Chopped up bitmaps in PDF files

On Mar 10, 9:59 am, "Neil Gould" <n...@xxxxxxxxxxxxxxxxx> wrote:
Recently, William F. Adams <willad...@xxxxxxx> posted:





On Mar 10, 10:37 am, "Neil Gould" <n...@xxxxxxxxxxxxxxxxx> wrote:
Until there is some proof to the contrary, I'll accept Adobe's word
(asDov Isaacshas stated in the past) for the engines' status over
anecdotal comments from a blogger without access to the source code.

The big difference is that making PostScript adds a step and a
transformation which direct exporting to .pdf bypasses.

Here's a message which Dov posted to the InDesign mailing list:

http://www.listsearch.com/InDesign/Message/index.lasso?129993

Note especially (3):
``(3) Yes, there are MAJOR differences between the PDF exported from
InDesign and PDF created via distillation of PostScript output from
InDesign...''

Which was the specific point I was trying to get at.

One shouldn't stop reading at the point of your excerpt. Dov stated:

"(3) Yes, there are MAJOR differences between the PDF exported from
InDesign and PDF created via distillation of PostScript output from
InDesign. Both yield PDF that is syntactically and semantically correct
per the PDF language specification. When creating PostScript from
InDesign, the assumption is that such PostScript is going to be
immediately printed. It is not optimized for creation of PDF and doesn't
deal with issues of PDF searchability, links, PDF optimization, etc. PDF
export yields PDF that is searchable and has various internal
optimizations. PDF export is also the only means of getting PDF with live
transparency and managed color from InDesign. Note that exported PDF quite
frequently uses double byte character encoding (CID encoding). Going
forward, the Adobe will continue to emphasize and improve support for
exported PDF as opposed to any functional improvements in the PostScript
route."

In other words, the "MAJOR differences" amount to the distilling to
PostScript method lacking searchability, links, PDF optimization, etc.,
which is to be expected as none of those aspects are relevant to printing.
Another "MAJOR" difference that I am aware of is exported PDF's insistence
on the use of CID encoded fonts (interesting that Dov restricts it to
"quite frequently", as I've not seen an instance where it isn't the case),
a REQUIREMENT of PostScript 3 that is ignored by some 3rd party RIPs. In
my experience, all other aspects such as whether the PDF contains live or
flattened transparency effects are under the control of the user.

Best,

Neil- Hide quoted text -

- Show quoted text -


FWIW, using the distillation of PostScript method does NOT prevent the
appearance of CID encoding in the resultant PDF file. It occurs far
less
than with direct PDF export though. If CID encoding is a big problem
for
someone, I suggest they worry more about their non-compliant RIP or
workflow software. CID-encoding is a very long established part of
both
the PostScript 3 and PDF specifications. Even PDF/X-1a permits it as
do the fairly conservative Ghent PDF Workgroup specifications.

Secondly, if you use transparency in your InDesign documents and you
really want to screw up your workflow, use the distillation of
PostScript
method of producing PDF. The very act of generating PostScript from
either Illustrator or InDesign results in flattening of transparency
and requires
you to know both the target color space and device resolution to even
begin
to get it "right." You end up with a non-repurposable, highly device-
dependent
PDF file.

BTW, the ability to fully search, touch-up, trap, etc. a PDF file is
certainly
relevant to printing!

- Dov
.

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