Scenario: You are designing a piece which will be printed in two ink colors. To enhance the impact of the design, you mix tints of the two inks to create additional colors.
Knockouts and Overprints
When different colored objects are stacked, fills and strokes apprear opaque because the top color knocks out, or cuts out, the area underneath when printed.
When overlapping colors are desired, the top shape must be designated to overprint instead of knockout.
Creating an Overprint
1 Select the object(s) on top that you wish to overprint.
2 Choose Windows>Show Attibutes.
3 In the Attributes window, check Overprint fill. Strokes can be set to overprint as well
3. To view the overprint on the screen, choose View>Overprint Preview.