To specify a halftone screen frequency and resolution:
In the Output panel of the Advanced Print Setup dialog box, do one of the following:
• To select one of the preset screen frequencies and printer resolution combinations, choose an option from the Screening menu.
• To specify a custom halftone screen frequency, in the ink list, select the plate to be customized, and then enter the lpi value in the Frequency box and a screen angle value in the Angle box.
Note: Before creating your own halftone screens, check with your prepress service provider for the preferred frequencies and angles. Also, be aware that some output devices override the default frequencies and angles.