We present the modelling of new indicators for old and intermediate age stellar populations based on the absorption features of Mg λ ˜ 5175 Å, Fe λ ˜ 4383 Å, and Hβ λ ˜ 5270, 4860 Å. Spectral models of stellar populations are convolved with the responses of the tunable filters of OSIRIS-GTC to provide photometric indexes with great abilities to separate age and metallicity effects. The new indexes allow us to obtain 2D maps of these features on the basis of a photometric approach and are built up to unreveal most relevant stellar population parameters.