OT: b/w printing of color pdf

[Christoph Litauer]

Hi,

some of our students recently noticed a problem, not exactly related to
cups. But I hope some of the ppd and postscript experts (Michael?) would
be able to give me some help.

I have some color postscript printers (e.g. HP CLJ 4700 or HP CLJ 4550)
driven by cups. ppds are from linuxprinting.org. Sometimes students want
to print a colored pdf document black-white (greyscale) on these
printers but the printer always prints color. Printing other documents
(Microsoft word, Firefox, etc.) result in greyscale output. I should
mention the students print the documents using Acrobat Reader 6.x under
Windows XP. They switch from color to greyscale in the printers property
dialog box (Paper/Quality).
The windows driver has been added with cupsaddsmb using e.g. the ppd
file on
http://openprinting.org/foomatic-db/db/source/PPD/HP/HP_Color_LaserJet_4700.ppd
But I noticed the same effect using the pdf converter of Robert Sander.

Searching the web brought me to
http://www.adobeforums.com/webx/.3bc46aff but no solution.

Comparing color vs. b/w print of the same document leads to the
following diffs:

8763c8763
< /E1 /ColorSpace findRes cs 0.24706 0.12157 0.0 sc
---
> /E2 /ColorSpace findRes cs 0.24706 0.12157 0.0 sc
8786c8786
< /E1 /ColorSpace findRes cs 1.0 0.62353 0.62353 sc
---
> /E2 /ColorSpace findRes cs 1.0 0.62353 0.62353 sc
8792c8792
< /E1 /ColorSpace findRes cs 0.81176 0.054902 0.18824 sc
---
> /E2 /ColorSpace findRes cs 0.81176 0.054902 0.18824 sc
8930c8930
< /E1 /ColorSpace findRes cs 0.80784 0.86275 0.99608 sc
---
> /E2 /ColorSpace findRes cs 0.80784 0.86275 0.99608 sc

and so on.

Any help is greatly appreciated. I can provide some print-outputs (PS)
if needed.

-- 
Regards
Christoph
________________________________________________________________________
Christoph Litauer                  litauer at uni-koblenz.de
Uni Koblenz, Computing Center,     http://www.uni-koblenz.de/~litauer
Postfach 201602, 56016 Koblenz     Fon: +49 261 287-1311, Fax: -100 1311
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