1. In a printing system which generates an output document from a print job, a computer-implemented method of matching color elements for objects having different source color definitions within the print job prior to printing, comprising: identifying all source colors to be printed within the print job and object type associated with each instance of a source color; identifying any source colors having at least two different source color definitions; wherein identifying any source colors having at least two different source color definitions comprises: for each object in the print job, transforming each object of the same object type using a prototypical color transformation; wherein the prototypical color transformation comprises an ICC-based profile; identifying sets of objects having source colors that match within a first tolerance level after the prototypical transformation process; for each set of objects having source colors that match, transforming each matching object's original source colors using a target printer's color space; and identifying any of the transformed colors of the matching objects within the set that do not match within a second tolerance level; for each source color having at least two different source color definitions, selecting one of the source color definitions in accordance with a predetermined criterion; deselecting any objects having source colors not intended to match in accordance with a second predetermined criterion; and assigning the selected source color definition to at least one other instance of the source color for that object type; printing an output document from the print job.