Spectroscopic analysis of SN 1999em. The three subfigures show comparisons between observed (black) and best-fit emulated spectra (blue); the best-fit has been determined through a maximum likelihood approach as outlined in Sect. 7.2. Each spectral comparison is combined with a table of the inferred parameters, the literature values from Dessart & Hillier (2006, D06), and the difference between the two. Since the observations have not been corrected for telluric absorption, we exclude the regions of strongest absorption from the fit (marked ⊕).