Energy spectra emitted by the accretion disc at times indicated in Fig. 2. The black curve corresponds to the rise to maximum (R), the red curve to the outburst maximum (M), the green curve to decay (D), and the blue curve to quiescence (Q). The solid line corresponds to the unilluminated case; the dashed line to the maximally irradiated case. Contributions from other components, i.e. white dwarf surface, boundary layer, hot spot, and secondary star, have not been included here.