Example CMDs for single stars (left panels) and binary (right panels) populations calculated with BPASS at three ages typical of clusters in our sample. Due to the nature of the binary models the CMDs are created assuming a small age spread for the population of  + / − 0.05 dex. The grid cells are 0.1 by 0.2 in V − I and M_V respectively. The grey scale is logarithmic in number of stars with the cell size. The dashed and solid contours represent when the density of stars in each cell is 0.1 and 1 respectively.