[Openicc] What is exactly needed for color management ... Rendering INtent

Richard Hughes hughsient at gmail.com
Tue May 31 14:46:01 PDT 2011

On 31 May 2011 22:02, Jan-Peter Homann <homann at colormanagement.de> wrote:
> In this case, the Default Rendering Intent of gstoraster will be used.
> Please make shure, that this is either perceptual or relative colorimetric
> with blackpoint compensation (if supported from GhostScript).

Sure, but choosing between perceptual and relative colorimetric isn't
always easy, a heuristic isn't going to cut it. This is really where
the platform support comes in, with patches to projects like cairo and
that kind of thing.

> From the implementation level, it would be much easier to change per
> document the rendering intent in GhostScript, than to update the toolkits
> for pdf print spool file generation and the applications which are
> triggering the print spool file generation...

I agree it would be easier, but probably not the right thing to do. In
Linux we're in a privileged position where we can add functionality to
an existing framework, write patches to applications and have it all
"just working" in as little as two distro release cycles (one for the
framework, one for the apps). That just can't be done in Windows and

> I would like to see in CPD an "Adcanced Option" which allows the user to set
> the Intent used in gstoraster as default INtent.

I've already asked the designers about rendering intents. None (!) of
them knew what those two words meant. To most people gamut clipping
and mapping is just technical gobbledygook. They just want the
specific colors they chose "red hat red" to be on the printed paper,
for graphs to look punchy and for text to look crisp. How it happens
under the covers isn't interesting, and if we have to make the user
choose a rendering intent per-document or per-printer then we've all


p.s. I know my "we've failed" emails might come across condescending
and handwavy, but I hope some people can see that I'm contributing the
code and putting my money where my mouth is. I feel passionately about
color management and I'm prepared to put in the extra hours to make it
"just work".

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