[scribus] b/w document: PDF greyscale or printer?
Hal V. Engel
hvengel at astound.net
Thu Sep 3 20:19:20 CEST 2009
On Thursday 03 September 2009 07:55:02 am Peter Nermander wrote:
> > now, and in the last few issues experienced problems. Eventually
> > it turned out that it was all caused by me exporting PDFs for
> > "Printer", not "Greyscale". PDFs exported for "Printer" are
> > actually RGB, not greyscale - even though the entire document
> > doesn't contain a single element in color. So a description of
> > what these two options do would be welcome :-)
> It has been mentioned several times on this list.
> Printer means PDF is exported as CMYK (the "printer" here means the
> profession, not the device)
I always thought that this means that the output will be converted to the
"Printer:" color space that is set in the Color Management Preferences dialog.
That color space could be a CMYK, RGB, Gray or device N color space depending
on the profile that is set in the Color Management preferences. And no it does
mean the "printer" (as in a device) and not the profession since the profile
set in the CM preferences dialog is for a specific device.
> Screen/web means RGB
I think Screen/Web means that the document will be converted to sRGB. Saying
that a document is converted to RGB is colorimetricly meaningless.
> (and is to be used for most desktop and office
> printers, because they are made to accept RGB data and trying to print
> a CMYK PDF to those devices mean that the CMYK will first be converted
> to RGB by the computer and then to CMYK again by the printer driver)
This is true on Windows and OS/X using vendor supplied drivers IF you don't
have a good profile for the printer/paper/ink/driver and work flow. Many of the
drivers used on *nix machines can also accept at a native level CMYK, Gray and
even in some cases device N input. For example the GutenPrint drivers
support RGB, CMYK, Gray and device N input at a native level on many printers
including the Epson R2400 I have.
> Grayscale means (if I understand right) CMYK without CMY (intended for
> when you print with only black ink).
I am not sure about this but I would expect a "Gray" color space document to
only have one subtractive channel.
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