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

[Graeme Gill]

Hal V Engel wrote:
> 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.

Black point compensation is Adobe's way of working around a fundamental
limitation of ICC profiles. Because profiles have pre-computed gamut
mappings embedded in their B2A tables, they can't actually tailor
their gamut mappings for the source colorspace gamut. [ICC V4 profiles
may address this issue to some degree.]

Black point compensation applies a limited form of "on the spot"
gamut mapping, namely adjusting the luminance mapping so that the
source black point maps to the destination black point.

Graeme Gill.