Re: PostScript Printing

[Tim Altom <taltom -at- SIMPLYWRITTEN -dot- COM>]

Yeah, Bruce, you've been taken in by the same misunderstanding that afflicts
a lot of people. PostScript isn't a graphics or presentation standard; it's
a printer language. And it really IS a language, with conditionals, math
functions, drawing elements, and all the rest that a true language needs.

Because it's a language, a printer driver must translate whatever it's
getting within its own body (Acrobat, which is a PostScript derivative,
Word, Quark, whatever) to the PostScript patterns. Adobe's driver does it
rather well, but a lot of other folks have written PostScript drivers for
their own printers, too. Some of those drivers don't do so well. Some older
printers don't use newer PostScript commands. It all gets very, very
complicated.

No, you don't embed file attributes that exist only in your tool. There is,
for example, no "conditional text" attribute from Frame that moves over into
the PostScript. Fonts are another whole issue. Type 1 PostScript fonts (if
indeed you're using PS fonts rather than TrueType) use "hints" to make the
letters look right, and different printer/driver combinations handle those
hints differently. So while YOU can't alter the fonts in the file, they'll
likely be worked over by your software.

In short, never trust that something labeled "PostScript" will work nicely
with anything else labeled "PostScript".

Also, you've intermingled two things: PS and PDF. Related, but not
identical. PDF in Reader may look the same, but printing it out is an
entirely different proposition. PDF is easier for most drivers to print,
because PDF is actually more page-centric than PostScript is. But it can
still produce horrible results with the wrong driver. In the main, a PS
driver will work very well with PDFs, but I've also found that PDF sometimes
prints better using PCL than PostScript, even though it's supposed to play
better with PS. I'm not sure what kind of driver the Lexmark is, but you've
proven that it didn't work well in this instance. I know that the HP driver
will produce excellent PCL, proving once again that PCL is useable for PDF.
Perhaps someone else on the list is more familiar with the Lexmark driver.

To answer your main question, though...no, PDF/PostScript isn't monolithic
and unchangeable. It's just more stable than anything else.

Tim Altom
Adobe Certified Expert, Acrobat
Simply Written, Inc.
317.899.5882
http://www.simplywritten.com
Creators of the Clustar Method for task-based documentation


>Hi gang. I have a query that hopefully someone can help with.
>
>I have always ass-u-me-d that when you PostScript a file you, in effect,
>embed the file attributes, fonts etc. and when printed, these fonts etc.
>cannot then be altered.
>
>Today we printed out a PDF file that is perfect using a HP4000 driver. We
>used a Lexmark Ultra S2450 driver in error and found that it had changed
>font style and the graphics had degraded terribly.
>
>My understanding of the process is obviously wrong as I have always thought
>that once a file is PostScripted and then distilled to a PDF file, that it
>cannot alter in appearance.
>


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