I am trying to create 4 color process or just plain halftone screens at 65 LPI with my HP Deskjet 820cse for silk screening. The problem is I can't get the LPI to change when it prints out. Regardless of where I change the frequency (Photoshop, Quark) the image always comes out the same. Also in Quark it says I can't print separations because the color is defined by the printers driver. I think this has to do something with HP's PCL language, but I'm not sure. What kind of printer do I need to do this (change the LPI) and print separations, or is it possible to do it from the printer I have know?