Left frame: a flickering flare of SS Cyg centred on 4545 Å  on 1998, July 8, as observed by Pearson et al. (2005). Right frame: ΔT_max as a function of wavelength of the comparison band for the observational data (filled circles) and the preferred fireball model (open circles). The solid and broken lines represent a linear least-squares fit to the data points (shortest wavelength point excluded). The location of the reference band is indicated by a cross. The dots with error bars are the average ΔT_max values of SS Cyg taken from Table 1, with the triangle representing the location of the respective reference band.