Opacity for each τ-bin in λ < 300 nm computed with Eq. 20 (solid blue curves) compared to the opacity (dotted black curves) for the F3V star. The rest of the coloured curves correspond to the opacity for the least opaque bin for each wavelength range. Dashed black line: Rosseland opacity mean computed with Eq. C.1. The bottom and top axis show the geometrical height and optical depth, respectively.