Evolution of orbit-varying quantities for Stokes parameters. The inclination is ι = 30°. The various panels show the evolution with the orbital phase φ of the various quantities that impact the Stokes parameters: the EVPA (red), the photon’s emitted energy ω = −k ⋅ u (red, in units of the observed energy), and the sine of the emission angle sin θ_B (green). The left column was computed in Minkowski spacetime and the right column in Schwarzschild. The top row was computed for a vertical magnetic field and the bottom row for a toroidal field.