Top: spectrum of DZ Cha in two different regions (black solid line) compared with the synthetic model (red dashed line). At red wavelengths the spectrum and model match each other and the lines have similar depths in both of them; at blue wavelengths the absorption lines of the spectrum are shallower than those in the model. Bottom: ratio of the equivalent widths of some selected lines across the spectrum plotted against the corresponding wavelengths. The ratios model/observations decrease as the wavelength increases. See text for details.