#Transfer Modes
There is a way to edit the PostScript code for screen frequency and angle
for Illustrator files. I have the code at work and can get it for you.
But there's another way. Use Adobe Separator to output the file (black
only), and but before you do, edit the PPD file for your printer to change
the line screen and screen frequency to that which you'd like. The choices
shown to you in Separator are read from the PPD file for your particular
printer.