Transfer functions |Γ_λ(ν)|² (top panels) and normalised transfer functions |Γ_λ, norm(ν)|² (bottom panels) for different values of L_transf/L_disc (left panels), α^* (middle panels), and f_col (right panels) at λ = 3000 Å. We show positive values of L_transf/L_disc with solid lines (case A) and negative ones with dashed lines (case B). The fiducial parameters are: M_BH = 8 × 10⁸ M_⊙, ṁ_Edd = 0.1, h = 20, Γ = 2, θ = 30°, E_cut = 150 keV, f_col = 1.7, R_out = 5000R_g, α^* = 0, and L_transf/L_disc = −0.5, 0.5.