[Openicc] [argyllcms] Re: Re: OT: PDF frustration

[Leonard Rosenthol]

On Oct 8, 2008, at 12:41 AM, Kai-Uwe Behrmann wrote:

> Am 08.10.08, 15:07 +1100 schrieb Graeme Gill:
>> Given there are DefaultXXX colour spaces possible to describe in the
> Resources section, this would free the OutputIntent to what Hal  
> already
> mentioned: the intented final device profile.
>

	That's a lovely thought - but that is NOT what the OutputIntent is  
for...

	DefaultXXX colorspaces are very good things - and for non-PDF/X(AE)  
documents can be used for the same purpose.  However, it should be  
noted that use of DefaultXXX colors will make the PDF larger, since  
you have to put them on every page AND in every Form XObject...


> So DeviceXXX colours can be specified enough. In the absence of a
> OutputIntent, a RIP can choose to retarget as it likes and selects the
> output device profile as it knows to its best.
> PDF-1.7 4.5.4 Default Color Spaces (p. 257)
>

	As I said, for a "standard" PDF, the OutputIntent (if present) is  
optional.  You can happily ignore it - in fact, Adobe Acrobat & Reader  
ignore it.  My point was that if you were to use PDF/X instead of  
standard PDF, then you MUST./SHALL respect and process the  
OutputIntent since that standard requires its use.


> I must say, previous to reading about the DeviceXXX Default Color  
> Spaces I
> took the OutputIntent like Graeme as a document describing hint and  
> not as
> a final decission.
>

	Right, because you were read the PDF Reference (or ISO 32000).  If  
you read ISO 15930 (PDF/X),. it's a different story.


>>>
> It should not be left too much interpretation. The main rationale is  
> to
> create a workflow with predictable results. In the context of
> CUPS/Ghostscript I see currently no way to tell a remote host to do
> proofing or to take the OutputIntent as final. So I would prefere the
> OutputIntent to be keept a safe place.
>
	
	The way to do it is to produce PDF/X instead of PDF - and then get  
Ghostscript updated to be a PDF/X conforming reader...


Leonard Rosenthol
PDF Standards Architect
Adobe Systems