Epson 1520 - Manual (Page 35)

To print the individual color channels from within Photoshop, first select each
spot channel required for output within the channels palette by turning on the
“eye” next to the channel name.
Next choose Page Setup from the File Menu and select the printer to be used
with the RIP. Click the Screens Button and uncheck the “Use Printer’s Default
Screens” box to allow the entry of new screen frequencies, angles and dot
shape for each spot channel to be printed. Also make sure to verify the Page
Size and check Registration Marks if needed.
Select each color channel within the Ink Scroll Box and enter a Frequency and
Angle for Each channel to be imaged to film.
Make sure to select a dot shape either round or ellipse. Much has been written
about the miracle powers of using an elliptical dot. Much of what is written is
slightly exaggerated. It can help, and should be experimented with but with
everyday style graphics where you’re not attempting to accurately reproduce a
fine work of art, you won’t see much improvement.
Output Directly From Photoshop
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