Distributions of counts (ADU pixel^-1) over the entire masked region of empty sky for NGC 2403 and NGC 6822 (top panels); Holmberg II, IC 10 (middle); and IC 342, NGC 6744 (bottom). The data are shown as solid lines, and the Gaussian best fits as dashed ones. The four bands are given by purple, blue, green, and red for I_E, Y_E, J_E, and H_E, respectively. The I_E VIS band counts have been multiplied by the ratio of the pixel area (×9) to be shown together with the NIR bands. In most cases, the data (traced by a solid curve) are so close to a Gaussian as to be indistinguishable from the best fit (shown by a dashed curve).