Potential colors for studying stellar populations

We try to find some colors that have the potential to study stellar age and metallicity from UBV RIJHK and ugriz colors using the simple population synthesis model of Bruzual & Charlot 2003 (BC03). The principal component analysis (PCA) (See Kong & Cheng 2001) and relative sensitive parameter techniques (see Worthey 1994) are used in this work. As a result, some colors such as (B - K), (R - K), (I - H), (B - V), (U - R), (R - I), are found to have the ability to break the stellar age-metallicity degeneracy partially and can possibly be used for studying stellar populations of galaxies.