Total PD as a function of inclination for varying optical depths: τ₀ = 0.5 (solid), 0.75 (dashed), 1 (dotted-dashed), 1.25 (dotted), and 1.5 (triple-dot-dashed). The illuminating source is taken to be (a) isotropic, (b) a blackbody unpolarized disk, (c) Comptonization in a slab, and (d) an electron-scattering-dominated disk. The wind opening angle α_w is fixed at 20° in cases (a) and (c) and at 40° in cases (b) and (d). In panels (c) and (d), the solid black line shows the PD of the incident radiation.