Process Color Printing On A One-color Press

For example, when you overprint a 100 percent solid of yellow and magenta, you expect to get a red hue but you don't. The actual result is an orange hue because magenta often has about 50 percent contamination with yellow. By printing yellow on top of the magenta, the yellow will undertrap during wet trapping. The result will be an overprint hue that should appear more as it should, namely reddish.