OT: b/w printing of color pdf

[Helge Blischke]

Christoph Litauer wrote:
> 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.
> 

I'd suggest to set up a b/w queue for the same physical printer
and set its default color model to gray (see. the following lines
from the PPD you use):
---snip---
*% =================================
*% Print Color as Gray
*% Chose NOT to use standard *ColorModel keyword because color on or off is simpler
*% =================================
*OpenUI *ColorModel/Print Color as Gray:  PickOne
*OrderDependency: 20 AnySetup *ColorModel
*DefaultColorModel: CMYK
*ColorModel Gray/On: "<</ProcessColorModel /DeviceGray>> setpagedevice"
*ColorModel CMYK/Off: "<</ProcessColorModel /DeviceCMYK>> setpagedevice"
*?ColorModel: "
   save
     currentpagedevice /ProcessColorModel get
	/DeviceGray eq {(Gray)}{(CMYK)}ifelse = flush
   restore
"
*End
*CloseUI: *ColorModel
---snip---

Helge



-- 
Helge Blischke
Softwareentwicklung

H.Blischke at acm.org