Spectrum generated by GYOTO for various viewing angles, computed for an injected single Gaussian line with μ = 6.9 keV and σ = 10 eV. The computations have been made for a non-spinning black hole with 10⁸ M_⊙, and for an integration disk surface from r_in = r_ISCO + 1 to r_out = 25 r_g. The equivalent width was chosen as 600 eV and was kept constant at all radii. The vertical dashed black line depicts the 6.9 keV, while the vertical dash-dotted gray line depicts 6.4 keV.