Xerox P8EX Spire CXP8000 Color Server - User Guide - Page 194

180 Black Overprint Chapter 4 - Basic Workflows Occasionally, white lines may appear around black text. The text may appear less dense than desired as a result of misregistration between color separations. Black Overprint is used to ensure that black text prints cleanly within a tint or picture area. The text appears in a richer, deeper black, with the underlying CMY values equal to those of the printed background. A knock-out occurs when you print only the topmost color. This results in lesser color density and can cause misregistration if separations are not perfectly aligned. When Black overprint is active, there are no knock-outs under the black text. Black overprint prints text over colored backgrounds rather than knocking out the background first. As a result, misregistrations are not visible. It is therefore recommended to use Black overprint in order to ensure best results when printing black text and graphics. ¾ To enable black overprint, from the Black overprint options, select Yes (Black Overprint applies only to 100% black). Note: Selecting No increases the processing speed.