[Openicc] Print-colormanagement, application->CUPS->gutenprint

[PLinnell]

On Tuesday 19 April 2005 20:20, Hal V Engel wrote:
> On Tuesday 19 April 2005 08:11 am, Michael Sweet wrote:
> > Hal V Engel wrote:
<snipped>
> snip
>
> > I'm not sure what you mean about a black point compensation
> > option. The black point is usually specified as part of the
> > source profile in the application/document, so CUPS will get that
> > information (black point, white point, and other profile info) in
> > the print job, too.  Similarly, the printer profile specifies the
> > black point (and white point) for the given combo of media,
> > inkset, and resolution...
> >
> > Are you looking for an option to disable gamut expansion?
> >
> > Couldn't that be handled by the rendering intent option?
>
> Black point compensation is an option that is available in
> Photoshop's print preview dialog in the color management section. 
> I am not sure exactly what it does but I think it has something to
> do with how that darker parts of the image are handled during the
> color space conversion.  So I guess that it is part of the
> rendering intent in that it slightly changes how the image is
> rendered.  I also know that I get slightly better shadow detail in
> my prints if I use it.
>

A good summary of black point compensation:

http://digitaldog.imagingrevue.com/files/Black_Point_Compensation.pdf

BPC was also added in littlecms, and you can enable this option in 
Scribus. In my own setup its default is on.

From my experience, with RGB > CMYK it helps mostly with pictures 
which have shadows or which need subtle differences in shades in 
darker regions. I can also say I used the same in PS6 with photos in 
magazines with somewhat limited CMYK gamut and it does help.

Perhaps one of the Adobe folks on the list here or Marti Maria can 
explain the details a bit more what is involved in supporting it
<snip>

Peter