Example of the binning used to compute the Q values for the G2V star, using different numbers of {τ, λ}-bins. Similarly to Fig. 8, each grey dot corresponds to one ODF substep. For this star, the τ-separators in the UV in all the experiments are fixed at log τ = {−1.8, −4.2}. Columns, from left to right, show the cases for N = 6–9 bins. The red numbers show indices of the bins. The case for N = 6 has two λ-separators at 400 and 1600 nm. For more than 6 bins, bins 1 to 5 are kept identical, but more λ separators are added between 400 and 9750 nm. A similar binning set-up is used for the other stars with modified τ-separators in the UV and the λ separator between the short and long wavelengths for N > 6.