1. A method comprising the steps of: accessing pixel color data for a first pixel, wherein the pixel color data has a first color component and a second color component; accessing a first alpha value, from a set of alpha values, to modify the first color component of the pixel color data; and accessing a second alpha value, different from the first alpha value, to modify the second color component of the pixel color data, wherein the second alpha value is accessed from the set of alpha values.