1. A method of rendering an image described by a list of graphical objects, the method comprising the steps of: assigning objects in the list to at least one of a first set of objects and a second set of objects; rendering the first set of objects to an image store using a first rendering method that determines whether a portion of an object of the first set contributes to a rendered output of the first set of objects and, if so, the first rendering method renders the portion; and rendering the second set of objects to the image store using a second rendering method that renders each object in the second set independently of the other objects in the second set.