[cups.general] Howto force a printer to print Grayscale?

[Linuxhippy]

Hello Helge,

and thanks a lot for your response!

>It depends on the driver software you use. Please tell us how the
>printer is connected, post 
>(an URL to) the PPD, etc.
>  
>
Since the ppd's are packages as ugly rpm-installers I uploaded just the 
ppd to http://kewlstuff.de/canoni250.ppd
The printer is connected via USB, canon provides a special module for it 
(I think its a binary, stored in backend/canon_usb)
I had a look into it and it seems it isn't cups fault not to provide a 
grayscale mode, is there any way to pre-filter it ? :-(

Thank you in advance, lg Clemens