[scribus] Printing in gray

[Andreas Vox]

> -----Original Message-----
> From: Gregory Pittman [mailto:gpittman at iglou.com]
> Sent: Dienstag, 9. Dezember 2014 17:37
> To: Scribus User Mailing List
> Subject: Re: [scribus] Printing in gray
> 
> On 12/09/2014 10:55 AM, a.l.e wrote:
> > hi jehan
> >> Hi,
> >>
> >> On Tue, Dec 9, 2014 at 8:23 AM, Rolf-Werner Eilert
> >> <eilert-sprachen at t-online.de> wrote:
> >>>> An old laser printer: HP color laserjet 2840.
....
> >> Isn't it supposed to be possible to make a document with CMYK colors
> >> in Scribus and get it printed with the CMYK composition directly to
> >> the home printer (so if I say "Cyan only" color, I want only the cyan
> >> toner to be used)?
> >>
> >
> > i'm not 100% up to date on the topic nor a color / print specialist...
> > but from what i used to hear in the past, consumer printer expect to
> > get RGB (and the internally convert to CMYK for printing). so, if you
> > feed them with CMYK, the driver will first convert the file to RGB and
> > let the printer reconvert it to CMYK.
> >
> > if this is true, no, it's not possible to print cyan only on a
> > consumer printer.
> >
> But from what I understand, when you print directly from Scribus, whether
or
> not colors are RGB or CMYK shouldn't matter.
> Ultimately, this should be a solvable problem.

Unfortunately, printing directly from Scribus means sending a CMYK
Postscript file
to the printing subsystem (usually CUPS). What happens then depends very
much 
on the CUPS configuration and the hardware.
 
What ale wrote about consumer printers is mostly exact: they expect RGB data

and it's the printing system's task to provide it. CUPS will use Ghostscript
to prepare
the necessary RGB data. Internally, the printer still uses one or two Cyan
inks, 
but the user has no direct control on how colors are mixed. 

OTOH, HP color laserjet 2840 seems to have native PS support, so just
copying 
the Postscript file to the printer should cause it to print in CMYK. It's
just a 
question of circumventing CUPS.

/Andreas