Unix command for Watermark printing

Hi,

Can anybody help me out with the unix command for watermark.

i am using solaris 9. I have installed CUPS software. Printer driver supports watermark.
I would like to know the watermark option for text,font and fontsize.

lpr -P printername -o ________________ filename.

please help out with this.
thanks in advance.

I haven't personally used this.. But this link might help..

ImageMagick - Linux Command - Unix Command