Total 3D abundance correction Δ_3D−1D for the artificial Fe ii line with excitation potential χ = 10 eV at λ 850 nm (top) and λ 1600 nm (bottom) as a function of the equivalent width obtained from the 3D model. The fainter (green) curves and the thicker (black) curves refer to the intensity (μ = 1) and flux spectrum, respectively. The abundance corrections have been computed for three different values of the microturbulence parameter used with the 1D model, ξ_mic = 0.0 (dotted), 1.0 (solid), and 2.0 km s^-1 (dashed lines). The weak line limit coincides with the horizontal part of the curves at low log W_3D.