[Openicc] Ghostscript CMS [was: PDF frustration]

[Leonard Rosenthol]

On Dec 1, 2008, at 9:31 AM, Kai-Uwe Behrmann wrote:
>> The idea of the rendering intent is just to communicate to the CMS  
>> what is
>> requested for those colors in the document.  In PDF, you can set a  
>> rendering
>> intent.  The CMS will need to decide what it wants to do with that
>> information.  It may decide for perceptual intent for example that  
>> it will
>> do black point compensation.
>
> Bpc works only with relative colorimetric.

	Are you sure about that?  In all of the discussions around BPC, I  
have never heard anyone say this before.


> As I recently looked over the
> default CM settings, I remembered that many developers voted for five
> rendering intents here some time ago:
> http://lists.freedesktop.org/archives/openicc/2007q4/000963.html
>
> I do not know if and how this, or bpc as a separate option, could  
> make its
> way into PDF.
>

	There is a proposal before the ISO 32000 committee to introduce BPC  
into ISO 32000-2 (as an element of the graphic state, of course).  It  
will most likely pass at the April meeting of the committee.


> The native device colour spaces may not behave symetrical along the  
> gray
> axis. So gray should remain gray after applying a function to all  
> channels
> equaly.

	Maintaining values in the K channel (or any pure colourant, for that  
matter) is also an issue being brought up at ISO 32000 for discussion.


Leonard