Three-color image reproduction from two-color image lacking one primary color is tried. The two methods are presented : -(1) Channel Interpolation.-(2) Spectral Estimation. (1) interpolates the third color from a combination of remaining two colors. (2) estimates the spectral distribution of each color pixel using the spectral characteristics of input scanner. It is impossible to render perfect colors by two primaries theoretically, but some of them are well restored.