Comparison of observed and theoretical M_c/L,log t-relations for continuous-IMF (left panels) and discrete-IMF models (right panels), cluster mass of M_c = 10³   m_⊙, and variable lower limit of stellar mass m_l. The upper row corresponds to the optical, the lower one to the NIR passbands. The designations for the empirical data are the same as in Fig. 10. For the models dash-dotted blue lines (diamonds in the right panels) correspond to m_l = 0.01   m_⊙, solid green lines (triangles) to m_l = 0.1   m_⊙, and dashed red line (crosses) to m_l  =  1   m_⊙.