Experimental noise power spectra in the frequency range 0 to 5 Hz are reported for 100% T, analyte, and 0% T signals in atomic absorption spectrometry. These spectra are calibrated such that the r.m.s. noise observed in normal measurements can be predicted for a given integration time. A 1/{cauchy integral} noise component is observed in lamp flicker noise, flame transmission flicker noise, and analyte absorption flicker noise. © 1979.