The synthesized color–color diagram for the synthetic spectra of galaxies which were accepted in each case based on their χ² values from the fitting to SDSS spectra. We show the cases with χ² limit less than 0%, 0.2%, 0.5% and 1% and 5% greater than the minimum χ² value respectively. The bottom right plot presents the color–color diagram for all the spectra in the second library. The notation of the colors is the same as in Fig. 1.