The calculation of theoretical "screen effect " from the viewpoint of mutual matching of spectral tristimulus values of a CIE standard colorimetric observer with color negative films and color printing papers is described in this article. The corresponding peak value position, half band-width and peak value s allowance of Red, Green and Blue of color measurements of color negative films are provided. The metamerism analysis and error analysis for the color measurements of general wavelength values are given. The experimental results have boi'ne ont the analysis. Each peak value comforms to the data published by Kodak Co. and French Co., and is nearly equal to the data pxoyided by a foreign color printer. Our data will provide reference for workers engaged in color photography and research and design of photographic equipment.