[Openicc] Print and monitor Color Pipeline

[Chris Murphy]

On Jan 26, 2011, at 3:16 PM, Leonard Rosenthol wrote:
> 
> You need to watch this, since this is what Quartz does.  And while perfectly valid, many professional printers will go nuts about having text and vectors with ICC profiles assigned.  (just sat through ANOTHER presentation, just this morning, at the Ghent Workgroup where they ranted about this particular issue).

Speaking of Pleistocene era. The issue here is implementation. The tagging of objects with metadata is a.) not permission to convert; b.) might imply, but does not require, a particular kind of conversion; c.) wrong.

Because of weak implementations, there's a desire to basically lie about the color space of certain objects. Rather than treating those objects in a fashion commensurate with the output process, and convert them to be compatible to the mechanics of the printing process, the history is to ban tagging such objects rather than improve implementations. Black only text is a unique thing. Tagging it with an ICC profile isn't the problem, it's how that gets interpreted downstream into an action to preserve the L*a*b* values of that black text, rather than treat it as a unique kind of object:

a.) On a press, black only text needs to stay 100% K only.
b.) On a billboard inkjet printer, I likely want the blackest four color (rich) black the printer can produce within its ink limit.

And I'd want those behaviors to occur from the same PDF by default, because that's the most likely usage scenario. The use case where you might want the two blacks to match is imaginary, but I have no issue with a developer who wants to build a switch in software to allow that interpretation from the same PDF by their customers.

> 
>  
> If the OutputIntent of the print stream PDF is not identical with the ICC-profile of the current printer setting. The PDF-rendering and rasterizing should be done firstly to the document colorspace and than to ICC of the printer driver setting.
> 
> 
> Nope!   You should follow the rules for PDF rasterization and color management as defined in ISO 32000.

Yeah I agree. But we still have this issue where the OI is only honored if the PDF is one of the PDF/X's, and if it's PDF/X then the PDF version is 1.4 or less, and when the PDF version is 1.4 or less, then no profile can be ICC v4.


Chris Murphy
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