Color management with look-up tables now is becoming widely used and the ICC profile format adopts it. While it is a realistic solution in case that the specifications of scanners and printers have already been fixed, it is unrealistic to apply it to the development of scanners and printers. It is because colors and color values are not presumed until a controller and engine have been completed. It means that specifications must be changed on a trial and error basis to get the desired colors and much more time and money is spent by using look-up tables.A new interpolation method has been developed to reduce time and monetary cost by designing a controller and engine, and predicting colors done in parallel. For printers, Print Simulator was made public at PICS2000 in March 2000. In this paper, we propose a method to manage colors on a spectral basis for color scanners. The method seems to be practical because it requires less time and cost less while providing good accuracy. An outline of this method is written below:(1) Specific color patches are selected by the singular value decomposition method.(2) Spectral characteristics of a scanner are calculated with the color patches.(3) Based on the spectral characteristics on Red (R), Green (G) and Blue (B), the relationship between colorimetric values and RGB values input from a scanner is defined.