Left: average ΔT_max for all investigated CVs as a function of isophotal wavelength of the comparison band. Right: average ΔT_max of all individual light curves, weighted in proportion to their duration. The broken line is a linear least-squares fit to the data points (excluding the points referring to the W and U bands), weighted by the inverse of their standard deviations. The error bars represent the mean error of the mean. In both frames the location of the reference band (B) is indicated by a cross.