Comparison of the contribution functions for the Fe i 5434.52 Å line determined using ATLAS 12 (red lines) and MARCS (black lines) model atmospheres. The solid lines represent the line core, dashed and dotted lines represent distances from the core of 0.05 and 0.25 A respectively. Vertical lines correspond to centre of gravity for each contribution function. Note that the contribution functions for the MARCS model spectrum are cut off at the top of the MARCS model.