[cups] Windows bypasses cups drivers

[Maarten Suetens]

Hello all,

I'm currently trying to enforce grayscale printing at the company I work 
at through cups. I have added the printer (sharp mx2600n) to the cups 
server using the ppd file and on the web interface i set the color mode 
to black & white.

When i print from the cups server(CentOS 6.5) it does use the grayscale 
and when i add the printer in Windows using generic postscript drivers 
it also enforces the grayscale correctly. But the problem is that the 
generic PS drivers does not support duplex printing.  When i add the 
printer to Windows using printer specific PS driver, the settings 
configured on the server are completely ignored and prints are being 
made in full color.

Any help would be greatly appreciated.

Thanks in advance and kind regards,
Maarten