Synthetic values of as a function of B − V color for stars from Gunn & Stryker (1983, open circles) and Pickles (1998, filled squares), and for an average SN at various epochs, from −5 to + 30 days, based on the SALT2 spectral sequence. The natural effective filter set is that of the 4Shooter camera, chip 1, with SAO filters, given in Jha et al. (2006), Table 5. Only the difference between SN and stars are relevant here, not the absolute δU values.