CIE94 is the latest recommendation on color-difference formulas made by the International Commission on Illumination. The strongest trend incorporated by this formula is a linear dependence for chroma-tolerances with chroma. A potential hue-angle dependence for chromatolerances, as proposed by Dr. Kim at the University of Leeds, could have been masked in previous experiments. We have tested this potential hue-angle dependence through a new experiment, where chroma-tolerances have been measured with a CRT device by 12 observers, using a constant level of L*= 40, two chroma values of C*=20 and 40, and 12 hue-angles at 30° intervals for each one of these chroma values. Our results support the existence of a hue-angle dependence for chroma-tolerances, and agree with Kim's model proposed for this dependence. However, from the experimental data set employed by the CIE TC1-47 for the development of the forthcoming CIEDE2000 formula, we have found that the hue-angle dependence for chroma-tolerances for reported here is not a consistent effect.
M.M. Pérez, A. Yebra, R. Huertas, J.J. Damelincourt, M. Melgosa, "Are Chroma-Tolerances Dependent on Hue?" in Proc. IS&T CGIV 2002 First European Conf. on Colour in Graphics, Imaging, and Vision, 2002, pp 132 - 135, https://doi.org/10.2352/CGIV.2002.1.1.art00030