[Samba] Re: CUPS Print Quality -- WAS -- UPDATE Where are the ADOBE PS Drivers?

[Chris McKeever]

n Fri, 10 Sep 2004 09:52:34 +0100, Simon Hobson
<shobson-lists at colony.com> wrote:
> Chris McKeever wrote:

> >
> >The reason I ask, was that I thought (for some reason) that the CUPS
> >processing made the windows client driver independent - but if the
> >windows client uses the PPD - then I am thinking that I was mistaken
> 
> 
> The first step (as far as Samba printing is concerned), if not
> already feeding it the right format, is to pre-process the input file
> to extract device specific options and convert them to Cups
> parameters and generate a device-independent Postscript file.
> 
> It selects a set of conversion filters, typically using Ghostscript
> to generate a bitmap image and then encode this into the printers
> native format.
> 
> 
> If properly configured, there is no reason that Cups should not be
> able to produce output as good as any other driver. The quality you
> actually get will largely depend on the settings (particularly
> resolution and colour depth) for the PS to bitmap conversion, plus an
> element of how well the device dependent filter converts the
> resulting bitmap to the printers native format.
> 

I believe in my tests, it was becausae I was going to a non PS printer
using the generic HPLJ PPD -- and unfortunately, both the PPD's I
tested using the ppd test script failed

>  From the above, you can prbably imagine that if you use a generic
> PPD, you can use the same driver and PPD for all printers, but you
> won't get access to all the facilities available on a printer. If you
> stick with the Adobe PS drivers, then you can use the same driver for
> all printers, only the PPD is different.
> 

So - the PPD controls the print options - therefore driver
independence isnt fully achievable since you need the printer specific
PPD (if you want to be able to set printer specific information per
job)

from the howto:

"A postscript file that was created to contain device-specific ommands
for achieving a certain print job output on a specific target machine,
may not print as expectd, or may not be printable at all on other
models"

Now what would be nice (and who knows if at all possible) - if there
was a generic CUPS PPD, which gave general print options
(duplex/punched) -- when sent from windows into the cups spooled, cups
could extract what the client requested, use the PPD of the vendor to
ensure what was requested is available, recreated the PS file and send
it to the printer.  With this, the client could be completely
driver/ppd independent

from the howto:

"for real PS printers, DO NOT use the foomatic PPD's.  The original
vendor PPD's are always first choice"

Thanks for the information - if I am still off, I apologize....


> Simon
> 
> --
> Simon Hobson MA MIEE, Technology Specialist
> Colony Gift Corporation Limited
> Lindal in Furness, Ulverston, Cumbria, LA12 0LD
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> 
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