Portion of the spectra of three SGB stars of NGC 1851, including the strong Fe line at 4202 Å (AS31, AS29, and A10). Spectra of the first two stars have been shifted vertically for clarity. This is one of the fifteen strong Fe lines used in our Fe abundance derivation. The areas hatched in red and blue mark the regions used to evaluate the line index appropriate for this line as described in the text (red is the in-line region, blue is the reference one). The average flux within each of these regions are shown as horizontal dashed lines.