定量研究了半色调印刷品的光谱反射率规律。在分程Clapper-Yule光谱反射率模型的基础上，通过引入光学网点扩大参数w修正了纸张和油墨的反射率与网点面积率之间的非线性关系，建立了考虑光学网点扩大的新光谱预测模型。数值计算表明：新模型的预测值修正了原分程模型预测值低于实验值的缺陷。半色调印刷品的墨点和纸基反射率是网点面积率和光学网点扩大参数w的函数，采用分程Clapper-Yule模型预测印刷品色彩必须考虑网点面积率和参数w对反射率的影响。

This paper quantificationally analyzes to the law of spectral reflections for color halftone prints. Based on the branch-path Clapper-Yule model of spectral reflection, the new spectral prediction model, taking into the optical dot gain account, has been established by introducing an optical dot gain parameter w to model the nonlinear relation between the dot area fraction and the reflectance of paper and ink. The numerical simulation of the new model shows that the prediction values are higher than the reflections of the branch-path Clapper-Yule model, which has modified the defect in the previous models. The reflections of paper and ink is the function of dot area fraction and optical dot gain parameter w, and the color of halftone prints predicted by the branch-path Clapper-Yule model must consider the effects of variation of dot area fraction and the optical dot gain parameter w on the reflections.