Measured (V − I)₀ spread as function of I-band magnitude for stars observed in dw1322-39 (black dots) in comparison with expected uncertainty derived from our artificial star tests. The red squares correspond to the mean values binned over 0.25 mag steps. The solid lines correspond to the 1, 2, and 3σ levels, the dotted line to the 75% completeness limit. The remaining galaxies are shown in Fig. A.2.