Polarized spectrum of a standard accretion disk (3 < r < 3000) viewed at different inclinations: i = 30° (red solid line), 60° (blue dashed), 80° (black dotted) as a function of dimensionless photon energy x = E/kT_*. Panel a: normalized luminosity x l_x. Panel b: polarization degree. Panel c: polarization angle. The lower subpanels show the errors in the corresponding quantities when computations are done with approximate expressions Eqs. (35) and (36) for the bending angle and lensing factor. We note that the error on x l_x is relative, while the errors on PA and PD are absolute.