I. Introduction
As printing technology has been moving forward accompanied by higher and higher printing precision, the use of spot color increases so continually that spot color matching tech has been developed all the way. At present, most manufacturers in China still use a hand mixed color-matching system that submitted by the designer who sometimes designs the basic color mixing formula according to Pantone color reference and then fine adjusts it comparing with the original color or sometimes designs it by trial and error. The hand-mixed method has shortcomings of wasting of time and materials and highly depends on experience of the handler.