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Jacob,
The PostScript feature in question converts all R=G=B vector graphics
and/or text to PostScript grayscale. If an application program feeds
R=G=B to GDI, that is exactly what is passed on to the PostScript driver.
We are not aware of any circumstances otherwise. What do YOU mean by
"meant to be gray?" If an end-user or a GDI-based program for that matter
defines a gray as R=128,G=128,B=127 ... you are correct in that the
PostScript driver will not convert that to grayscale. The PostScript
driver does NOT attempt to map "almost gray" to grayscale because that
could cause major problems and anyway, would not be the intent of the user!
For the RIP, I would most strongly recommend printing directly from
Acrobat Pro 6 to the PostScript aspect of such RIPs, not the "PDF input"
(which for the vast majority, simply does a convert PDF to PostScript,
anyway). In that case, use the Advanced features of the print dialog
to set the appropriate color AND transparency flattening options.
- Dov
At 7/23/2003 10:05 AM, Jacob Sch�ffer wrote:
>Dov,
>
>I normally do agree with your statements on these lists, but this time I
>beleive you fail.
>
><...any text or vector graphics, for which R=G=B (i.e., grayscale including
>pure black),
>yields grayscale PostScript.>
>
>Nope!
>
>Indeed, this might have been the intended behaviour, no doubt, but in cases
>where RGB should have been R=G=B it might not be so in the real world with
>GDI. Often GDI returns R<>G<>B for colours that were meant to be gray, and
>the setting you mention does NOT catch such 'gray', because the threshold
>for 'almost equal' doesn't catch it.
>
>Our CMYK PDF Creator does have a built-in (currently hard-coded - based on
>276 test jobs from MS Word) threshold value and a built-in 'almost equal'
>operator that catch any to us known such 'gray', however.
>
><... you cannot properly print RGB PDF. Bull! Using the "Advanced" function
>of Acrobat's print menu ...>
>
>How would you configure a native Acrobat 6.0 Pro to save a proper PDF for
>in-RIP separation on a PDF RIP the way you mention?
>
>Best regards
>Jacob Sch�ffer
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