Endpoint criteria for image permanence of color hard copy prints are studied based on a psychophysical study, using a set of color prints which have systematically altered densities and colors. Acceptable range of the density and color balance change from the original in various scenes are discussed. We confirmed that the current ISO criteria are useful in some degree as a simple estimation but we propose a new set of criteria which reflects human visual sense more accurately. The new criteria are applied to image stability evaluation of inkjet, xerography, D2T2, thermo-autochrome, Pictrograpy and silver halide color printing materials.