Comparison of the observed indices (black dots show the spectral pixels) with the predictions of the FIF best-fit models (magenta line), with an age of 0.81 Gyr and a metallicity of −0.19 dex. The blue and red regions correspond to the wavelengths where the pseudo-continua are measured and the white regions are the wavelengths where the index is measured. In the bottom panels the residuals are plotted as green diamonds. The gray lines and shaded regions are the median of the residuals and the average observed errors on the indices, respectively, while the black dashed line marks the 0.