Upper plot: emergent flux from a reference model atmosphere with ε_Si = −4.6, ε_Cr = −6.7, and ε_Fe = −5.1. Lower plot: emergent flux from the model atmospheres with modified abundance of individual elements minus the flux from the reference model. All fluxes were smoothed by a Gaussian filter with a dispersion of 10 Å to show the changes in continuum, which are important for SED variability. The passbands of the ten-colour photometric system are shown in the graph as grey areas.