Representation of the quiet Sun by a combination of models. Ratios of synthetic solar spectra of models A (blue) and E (red) to model C. The black line results by combining 57% of the model E spectrum with 43% of the model A spectrum. The spectral signatures are almost perfectly cancelled, implying that the combination of both spectra is equal to the model C spectrum. The latter has been demonstrated to accurately reproduce the observed solar spectra during the last two minima (Shapiro et al. 2010). Hence, a combination of spectra for models A and E reproduces the observed quiet Sun spectrum.