Two psychophysical techniques, the method of constant stimuli and the gray-scale comparison method, were used to determine color tolerances for three different color centers in the hue, chroma, and lightness directions in CIELAB color space. The same color-difference pairs were used as the stimuli in both experiments. Although the results followed the same trends, they were different for the two techniques. Based on comparison of the validity and precision of the results, as well as the ease of implementation, use, and analysis, the method of constant stimuli is the preferable method.