Top: assumed temperature (solid line, left-hand scale) and emitting area (broken line, right-hand scale) evolution of a black body used in simulations of the brightness development of a flickering flare as a function of time. Bottom: calculated profiles of a simulated flickering flare in the bands of the UBVRI system. The inset shows the times of maxima (dots) as a function of the isophotal wavelength of the respective bands, together with a linear least-square fit (broken line). See text for details.