高保真印刷技术通过在CMYK的基础上增加其他原色的方法，达到扩大色域的目的，增加的原色与CMYK之间存在替代关系，替代关系可以简化复杂的高保真多色分色模型，并提高其精度。以CMYKRBG七色高保真模型中R为例，设计了渐变测控条，打印输出并测量了各级网点密度，采用多项式回归算法，拟合出了间色平衡曲线，建立了R与MY的替代方程，通过设置间色替代率，获取了R与MY之间的颜色替代量，最后设置了4组不同的间色替代率，通过色差确定了合适的间色替代率的取值范围。实验结果表明：确定的间色替代率在0.2左右，可以提高分色模型的精度。

By adding some original colors to CMYK, Hi-Fi printing technology can expand the gamut. The original colors added have substitution relation with CMYK. The substitution relation can simplify the complex Hi-Fi color separation model and improve precision. The R in CMYKRGB 7 colors Hi-Fi model was taken as an example, and gradient-type control trip was designed and printed. The density was measured. The mid-color balance curve was fitted by polynomial regression algorithm to build the alternative equation. The substitution between R and MY was obtained by setting the mid-color replacement rate. 4 groups of different mid-color replacement rate were set and ΔE was measured to determine the proper range of the mid-color replacement rate. The results showed that the accuracy of the separation model is improved by setting the mid-color replacement rate as 0.2.