Measuring low frequency data using conventional methods has presented problems in some systems with the values of key parameters often being obtained by extrapolation. Laplace transformation of coulostatic transients has potential advantages in this frequency range, although difficulties may arise with the resolution of the long-term transient decay. In this work the effect of measurement resolution is examined. It is shown that the low-frequency impedance response of a corroding system may be obtained using coulostatically induced transients determined at achievable let els of measurement resolution. If the unresolved transient decay is negligible, as is usually the case, no lower bound is placed on the frequency range of the impedance spectrum. On the other hand, when a very slow long-term decay makes a significant contribution to the impedance data determined, the lower bound of the frequency range is limited by the duration of the transient. However, in this case, the adverse effect on the frequency range is minimised by the longer duration of the resolvable transient describing a given percentage of the potential decay. A key feature of the analysis of coulostatic transients is that the response is recorded after the application of a perturbation of very short duration and therefore only information on the interfacial impedance is obtained. Thus the effects of a possibly dominant bulk electrolyte impedance are eliminated.