GCR: Abbreviation for Grey Component Replacement.In process colour printing,different compositions of the three colours yellow,magenta and cyan form different degree of greyness which are replaced by corresponding percentage of black screen dots.

• 灰部置换:英语是灰部置换的缩写。在四 色彩印中，用不同百分率的黑色网点代替不同份量的灰度；即是代替不同份量的黄、洋红 和青蓝的组合。