Overview of the ⟨3D⟩ − 3D line formation differences given in abundances displacement Δlog ε vs. equivalent width W_λ for the Fe i and Fe ii fictitious spectral lines with the excitation potentials χ_exc = 1.0 and 4.0 eV including the Sun, TO, RG and dwarf simulation (from top to bottom). The averages on layers of constant geometric height ⟨3D⟩_z (black dashed), constant column mass density ⟨3D⟩_m (black dotted), constant Rosseland optical depth ⟨3D⟩_Ross (black solid) and at 500 nm ⟨3D⟩₅₀₀ (orange dashed triple-dotted lines) are indicated. Furthermore, we show 1D models (red solid), -averages (blue dashed) and (green dashed lines). The microturbulence of ξ_turb = 1.0 km s^-1 has been used throughout. Notice the different ordinates.