Age–metallicity relation for clusters studied in this work compared with the literature (see Table 5). Values derived from two-color Strömgren diagram (black diamonds); values derived by Perren et al. (2017) using the ASteCA package (open circles); low-resolution spectroscopic metallicities expressed in ZW84 scale (gray squares); high-resolution spectroscopic metallicities in ZW84 scale (blue squares); values obtained from RGB slope method given in ZW84 scale (open triangles); values derived from fitting of theoretical isochrones to optical data (crosses); values derived from fitting of theoretical isochrones to data in Washington system (open crosses). Red squares and open circles indicate measurements from this work presented in Fig. 10 for comparison. Overplotted theoretical models are as in Fig. 10.