Normalisation procedure for a two stars with T_eff ~ 4600 K (left) and T_eff ~ 5300 K (right) shown by the wavelength region about two lines of the magnesium triplet. Top: the second iteration of SPB, middle: first iteration of SPC, and bottom: final solution from SPC. The stellar parameters (T_eff, log g, [M/H] and [α/Fe]) and goodness of fit over all the AMBRE:FEROS wavelengths (log χ²) are shown. The synthetic spectrum interpolated to these parameters is shown in red, while the normalised observed spectrum is shown in black. The difference between observed and synthetic spectra is also shown at 0.0.