The stellar population models dramatically progressed with the arrival of large and complete libraries , ELODIE , CFLIB ( =Indo-US ) and MILES at a relatively high resolution .
We show that the quality of the fits is not anymore limited by the size of the stellar libraries in a large range of ages ( 0.1 to 10 Gyrs ) and metallicities ( -2 to +0.4 dex ) .
The main limitations of the empirical stellar libraries are ( i ) the coverage of the parameters space ( lack of hot stars of low metallicity ) , ( ii ) the precision and homogeneity of the atmospheric parameters and ( iii ) the non-resolution of individual element abundances ( in particular [ \alpha /Fe ] ) .
Detailed abundance measurements in the large libraries , and usage of theoretical libraries are probably the next steps , and we show that a combination between an empirical ( ELODIE ) and a theoretical library ( Coelho et al .
2005 ) immediately improves the modeling of ( \alpha -enhanced ) globular clusters .