About overprinting
If you have not changed the transparency of your artwork with the Transparency panel, the fills and strokes in the artwork will appear opaque, because the top color knocks out, or cuts out, the area underneath. You can prevent knockout by using the Overprint options in the Attributes panel. After you’ve set your overprint options, you can preview the overprinting effects on‑screen.
InDesign also has overprint simulation, which is useful for simulating the effects of overprinting spot and process inks on a composite printing device.
Black ink applied to text or native InDesign objects is overprinted by default to prevent misregistration of small black-type characters positioned over color areas, or of color areas outlined with black lines. You can change black ink settings using Appearance Of Black preferences.
Your design workflow may require a certain color to be set to overprint. For example, you want to print all the text in your publication in a specific color. Consider the following options:
-
Create an object style that uses the spot ink as the fill or stroke with a matching overprint fill or stroke.
-
Create a separate layer for objects that contain your spot color and assign them to black.
-
Create a composite PDF and change overprint settings within the PDF.
-
Assign overprint settings in your RIP.
-
Apply overprint settings to an image or object and add it to your library, or edit a placed file in its original application.