A modified CIECAM02 colour appearance model, named CIECAM02-m2, is proposed to enable CIECAM02 to predict the simultaneous contrast effect. The structure of the CIECAM02-m2 is a development from CIECAM02, and contains two different procedures for modifying the reference white; one is for lightness and the other is for hue. The model was tested using a data set accumulated in this study and the LUTCHI data. The CV values for three colour attributes between predictions and experimental data were used to evaluate the accuracy of the model. The low CV values obtained show the performance of the CIECAM02-m2 model to predict the simultaneous contrast effect satisfactorily. (C) 2007 Wiley Periodicals, Inc.