Duration of achromatic phase as a function of R_Ein, the scale of variations in the microlensing map. The dots correspond to the median and the vertical bars indicate the range from the 16th to 84th percentile for the sample of four models, two different κ and γ pairs, five different s values, and 15 color curves that have been investigated, where we average over all parameters not shown on the x-axis. From left to right, R_Ein corresponds to (z_s, z_d) = (0.99, 0.48),(0.77, 0.32),(0.55, 0.16),(0.99, 0.16).