Stellar mass-to-light ratios in the I band (open circles) and [3.6] (filled circles) as a function of V − I color. The models of Bell et al. (2003), Portinari et al. (2004), Zibetti et al. (2009), and Into & Portinari (2013) have been revised according to the fits in Table 4. Contrary to the case of B − V (Figure 3), there is little correlation: V − I is not a good primary indicator of _*, though it does have some value as a secondary indicator when combined with B − V (Figure 8).