chromospheric condensation with a low optical depth and stationary beam-heated layers just below this consensation. A very strong dependence of the WL emission on the local atmospheric conditions and thus “penetrability” of the atmosphere by flare-accelerated electron from the reconnection site was indicated also earlier by [@2005ApJ...618..537C].

[@2006ApJ...641.1210X] by using multiwavelength high-resolution observations showed that the emission energy budget cannot be ballanced if only a direct heating of the emitting regions is considered. An alternative explanation for the white-light emission observed during WLF is that it is a combination of the spectral continuum (Paschen and Balmer continuum), which forms in the chromosphere, and a photospheric emission, which is stimulated not by beams, but by radiative heating from the chromosphere. This so called ‘backwarming’ model was devised by [@1989SoPh..124..303M]. It seems that for at least some flares classified as WLFs, mostly the strong ones, the presence of a radiative backwarming is necessary to explain the observed VL intensities .

[@2008ApJ...688L.119J] reported on a very fine structure of white-light emission, where the points of brightening were not larger than 300 km, much beyond the resolution of synoptic telescopes. The authors concluded that with a sufficient resolution, every flare must have a white-light 