Line asymmetries of the Fe i λ5500 Å with E_i = 3 eV as a function of the dynamical phase φ_d. Line strength changes in order of oscillator strength with log gf₁> log gf₂> log gf₃ > log gf₄. Dynamical phase zero coincides with the velocity reversal from contraction to expansion in the photosphere. The line asymmetry curves are shifted by 0.5 dex relative to each other for clarity.