Median root mean square (rms) level of background column density fluctuations as a function of background cloud column density as measured in a 1′ × 1′ sliding box over the clean background image of the Aquila complex produced by getsources from the high-resolution column density map. The error bars correspond to the interquartile range of background fluctuations about the median level in each column density bin. The straight line represents a weighted power-law fit to the data points above N_H2 ~ 2 × 10²¹ cm^-2.