Panel a) Emerging flux of radiation, H  [erg   cm^-2   s^-1   nm^-1] , near the Lyman series of H I for the ATLAS12/MHD-Q model of T_eff = 25   000 K and lgg = 4.0. Panel b) The ratio of the emerging fluxes for models calculated with different description of the occupation probability formalism (see text). Panel c) The same as panel a), but for the Balmer series of H I. Panel d) The same as panel b), but for the Balmer series of H I.