Spectrum and PD for radiation emerging at an inclination angle 75° for different optical depths, τ = 0.67 (cyan), 1 (red), and 3.33 (brown). The blackbody temperature is fixed at T_BB = 1 keV, with a slab density n_H = 10¹⁹ cm⁻³. Solid (dotted) lines depict the results for a slab in the PIE (CIE) configuration. The horizontal black line marks the value predicted by Chandrasekhar (1960) computations for a 75° inclination angle.