1. A method of blending a plurality of mutually overlapping graphical objects in a digital document processing system, wherein said plurality of graphical objects is arranged in an ordered stack that includes at least one static object and at least one animated object, each of said objects comprising graphical content and having at least one blending parameter for at least part of the object associated therewith, the method comprising: (a) blending the content of said static objects to form at least one composite static object, taking account of the respective blending parameters of the static objects; and (b) blending the content of the animated object and the or each composite static object, taking account of the blending parameter (s) of the animated object.