Noise performance in imaging arrays is often specified simply by the variance of the pixel levels. In this paper a more complete characterization technique is presented, based on the spatial-frequency power spectrum of the noise data on the detectors. This is seen to provide additional information for cases in which the noise spectrum is nonwhite. Experimental data demonstrate the nonwhite nature of the spectrum under certain conditions, especially resulting from spatial correlation of detector nonuniformity and from sampling-lattice-related artifacts in the data