Optical depth for the two-photon annihilation (﹩{\tau }_{\gamma \gamma {\rm{,}}{e}^{+}{e}^{-}}﹩) and effective optical depths for photomeson production (f_pγ), Bethe–Heitler pair production (f_BH), and inelastic proton–proton collisions (f_pp) for two values of τ_T. The emission radius is set to R = 10R_S. For the photomeson production, the Bethe–Heitler process, and proton–proton collisions, the proton escape timescale is set to t_* = 100R/c.