针对光谱反射率空间并不是一个有效的基色色料线性混合空间的缺点，提出了建立基色色料线性混合空间的三项原则。根据不同原稿色料光学特性的不同，将原稿分为透明色料连续调原稿、不透明色料连续调原稿、半色调原稿(半透明色料)，并针对这三类原稿分别构建能真实反应原稿色料真实物理维度的光谱线性空间，以不透明色料原稿为例进行实验验证。实验结果表明，根据原稿色料光学特性建立的色料线性混合空间是一个有效的线性混合空间，在其上的光谱预测能真实反映原稿基色色料的数量和近似得到基色色料的光谱形状。

Aimed at the defect that spectral reflectance space is not a valid primary pigments linear mixing space, three principles of establishing the primary pigments linear mixing space are presented. The manuscripts are divided into three types, transparent pigment continuous tone, opaque pigment continuous tone and halftone (translucent pigment) according to the different optical properties of different original pigments. The linear spectral spaces of real physical domain that can reflect original pigments really for these manuscripts respectively are built up. Experimental verification is carried out taking opaque pigment manuscript as an example. Experimental results show that the pigments mixing linear space according to optical properties of original pigments is a valid linear mixing space, of which the spectral can correctly estimate the numbers of primary pigments and approximate the spectral shape of each primary pigment.