WHAT IS OVERPRINTING?
Overprinting is when one ink is printed on top of another instead of knocking the shape out and printing directly onto the paper, resulting in the mixing of colors. Black and especially black text is often set to overprint on top of other colors, creating a darker black. Objects that are in white should never be set to overprint to prevent them from disappearing.
WHAT IS KNOCKOUT?
Knockout is the process of removing one color from below another to prevent the mixing of colors. When two knocked-out images overlap, the bottom portion is knocked out or removed so that it doesn't affect the color of the top image.
WHAT IS TRAPPING?
When one element is knocked out of another, there could be a gap or white space when printed on press. Therefore trapping software is used to intentionally overlap the colors to compensate for possible mis-registration on press. Traps are very small, only 0.25 points.
