[cups] cups Digest, Vol 77, Issue 2

[Gregory Morse]

Helge,

That explains a lot. So it's not the underlying driver, but rather the PDF
to Post Script conversion routine that is different. Thank you so much for
the explanation. I will email you directly with a sample PDF file and to
continue the conversation. Thank you. Thank you. Thank you!

- Gregory

Gregory Morse
gmorse at morseinc.com


On Fri, Apr 10, 2020 at 12:00 PM <cups-request at cups.org> wrote:

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> Today's Topics:
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>    1. Re: Printing quality differences when printing pdf using CUPS
>       and app on MacOS (Helge Blischke)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Thu, 9 Apr 2020 23:00:36 +0200
> From: Helge Blischke <helgeblischke at web.de>
> To: "The CUPS user discussion list." <cups at cups.org>
> Subject: Re: [cups] Printing quality differences when printing pdf
>         using CUPS and app on MacOS
> Message-ID: <ED47524B-B206-40A6-A30D-E30C95EFF144 at web.de>
> Content-Type: text/plain;       charset=utf-8
>
>
>
> > Am 09.04.2020 um 19:24 schrieb Gregory Morse <gmorse at morseinc.com>:
> >
> > Greetings. I have a strange situation I'm trying to find if anybody can
> > help with.
> >
> > I am printing the same PDF file on MacOS Catalina in two different ways:
> 1)
> > Using CUPS on the command line and 2) using an app on the mac, i.e. Adobe
> > Acrobat Pro or Adobe InDesign. Both are generally working well, but there
> > is a small, but important issue. When I print the files using CUPS the
> > print quality is slightly degraded compared to the output from CUPS, it's
> > subtle, but different. What I've noticed is that the output from CUPS is
> > the same as the output when printing from the Apple Preview App. So for
> > some reason Apple Preview and CUPS print the file differently than Adobe
> > InDesign and Acrobat. It's so strange, a PDF is a PDF right? Any
> > suggestions?
> >
>
> Well, printing an existing PDF from the preview app or by command line
> commands (lp command)
> both initiate the same sequence of CUPS filters that convert the source
> PDF to
> the data format the printer requires. the first step in this case is
> executing
> one of the cgpdftosomething filters (where something is one of ps
> (postscript), pdf, or raster).
>
> When printing from Acrobat (reader or professional) or InDesign, the first
> step is done
> by the Adobe program itself, namely generating a PostScript job which is
> then transformed
> by a CUPS filter pstosomething.
>
> So it is plausible that both transformation sequences lead to (slightly?)
> different results.
> To dig into the details, I’d propose you send me a sample PDF, I then
> could perform a
> detailed analysis of what happens, especially with respect to color
> handling.
>
> Helge
>
>
>
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> End of cups Digest, Vol 77, Issue 2
> ***********************************
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