A revision of the CIECAM97s model

The CIECAM97s model was adopted by the CIE in 1997 for colour imaging appli cations. It includes forward and reverse modes. Some problems in using this model were found in recent field trials. This article suggests revision to the model in two respects: (a) to make the lightness (J) zero when the Y t ristimulus value is zero, under ail surround conditions: (b) to modify the chromatic induction factor (Nc) from 1.10 to 0.95 for the dim surround cond ition. To avoid confusion, it is suggested that thr revised version of the model De designated CAM97s2. The article also describes an alternative mode to achieve a more nearly exact reversibility between the forward and rever se modes. (C) 2000 John Wiley & Sons, Inc.