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

Jan-Peter Homann homann at colormanagement.de
Wed Jun 1 00:22:35 PDT 2011

Hello Richard and all,
If you deal with rendering intents, you either need a default setup and 
a place where the user can make a choice.
If you don´t offer the choice as an advantaged option in CPD, the 
framework and GUI for this choice has to be implenented in the EVERY 
application and must be coordinated with the toolkits for PDF print 
spool file generation.

This is definetely much more work than a simple patch.

If the toolkits for print spool PDF deliver DeviceRGB PDF files, which I 
expect will be the standard for the next 1-2 years, we MUST have 
gstoraster default wich is either perceptual or relative colorimetric 
with blackpoint compensation (I prefer second). Please make shure, that 
the gstoraster default is NOT relative colorimetric without blackpoint 
compensation, because this will lead to loss of details especially for 
plain paper settings.

Best regards

Am 31.05.11 23:46, schrieb Richard Hughes:
> 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
> OSX.
>> 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
> failed.
> Richard.
> 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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