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On Sat, 17 Jun 2000, Win Day <winday -at- home -dot- com> wrote:
>At 09:20 AM 13/06/00 -0400, you wrote:
>>1) If you are providing a file for a service bureau, follow their printer
>>requirements, period.
>>
>>2) If you want to have well-formed PDFs or expect assistance
troubleshooting
>>Acrobat woes, use the prescribed Adobe printer drivers and PPDs. Period.
>>
>>3) If you want both of the above, do it twice: create one for your service
>>bureau and one for distribution/troubleshooting.
>
>Yabbut...
>
>The first two statements provide contradictory advice.
>
It seems so. I would contend that there is a key word missing from the
first statement: PostScript. But if we make that change, I'm not sure
that the third statement makes sense. On the other hand, I'm not
entirely sure what the context of the third statement was in the first
place...
The key concept underlying my rewording of the original writer's first
statement is that raw PostScript is highly specific to a particular printer
model, so that if you are sending *PostScript* files to a service bureau
it is essential for you to follow their specifications exactly.
The process of converting PostScript to PDF "distills out" the printer-
specific parts of the PostScript code to leave behind the underlying
code that specifies all the glyphs and graphic object that comprise
each page of the document. *In*theory*, you should be able to distill
any PostScript file, prepared for any printer device, to produce PDF.
In practice, though, this does not work reliably because many aspects
of the page description (that underlying stuff) are affected by the
printer driver's knowledge of the device's capabilities and limitations.
The most obvious example is that if you distill a PostScript file that
was generated using the driver for a monochrome printer, the PDF file
will also be monochrome because any color content in the original
document (color graphics, for example) will have been totally absent
from the PostScript file. Other, more subtle printer-specific changes
can include adjustments in the text spacing to match the specific
printer's font metrics. The result of this is that the only way to
produce consistent PDF is to use a printer driver that is device-
independent, and this is where the Distiller printer driver (built from
the appropriate AdobePS core driver plus the Distiller PPD) comes in.
>The reason we provide PDF files to WHOEVER we provide them to is so the
>end-result printed product looks the way we want it to, correct?
>
>So, I must provide the service bureau with PDF files distilled from PS
>files created for their specific printer, right? And that will guarantee
>the expected printed output?
>
Nope. If you are providing PDF, it should have been created using the
Distiller printer driver. Your service bureau's system will automatically
add the necessary printer-specific code to the PDF page description
code before it sends it to the output device, whether it is a high-volume
laser printer, a Docutech, or an image setter. Only if you are sending
the raw (undistilled) PostScript do you need to use the device-specific
printer driver.
>But I can use the generic Adobe PS driver to create PS files and distill
>them to PDF for everyone else?
>
No, you should NEVER use the "generic Adobe PS driver". You should
ALWAYS use the specific Adobe Distiller printer driver, which is not the
same thing. Both drivers are built with the same AdobePS driver core,
but use different PPD (PostScript Printer Description) files. Adobe
provides a PPD for a generic printer so that in a pinch you can create
a driver that will probably work with a physical printer that you don't
have a specific driver for, but this generic driver does not work nearly
as well for PDF generation as the Distiller driver does.
>Sorry, I don't get it. If I have to use the specific printer driver for
>the files going to the service bureau, how can I get away with using the
>generic driver for every other purpose?
>
>Or to look at it the other way around, if the service bureau can't use the
>files I created with the generic printer driver, how can EVERYONE else?
>
When creating PDF, regardless of what you will be using the PDF for, you
should use the Acrobat Distiller printer driver. NOT the generic PostScript
printer driver, and NOT the printer-specific driver. But having said that,
the reality is that you may still need to generate a separate PDF file that
is distilled with different job options settings to send to your service
bureau.
The reason is that your service bureau may have a high-resolution output
device that can take advantage of higher graphics resolution in the PDF
file. For other purposes, such as distribution on CD-ROM or via a website,
you would probably want to distill with moderate resolution settings to
keep the file size more reasonable. But both PDF files would be distilled
from the same PostScript file, which should be one that was generated
with the Distiller printer driver.
My opinions only; I don't speak for Dialogic or Intel...
Fred Ridder (Fred -dot- Ridder -at- Dialogic -dot- com)
Senior Technical Writer
Dialogic, an Intel Company
Parsippany, NJ
