In order to obtain high spatial resolution microchemical data from beam-sensitive materials, alternative techniques which avoid the use of fine probes, such as energy-filtered imaging techniques must be used. Robust quantification procedures are currently under development. The quantification procedure which yields images whose intensities are proportional to the elemental concentrations (atoms per unit volume) has already been determined. The net core-loss intensity images, Si, can be corrected for diffraction contrast by normalization with low loss images, whereas thickness variations are corrected by normalization with t/λ, maps. This procedure has been shown to give the correct value for the concentration ratio between two phases for a single elemental map.1 Determining concentration ratios between two elements in the same phase can actually be simpler, in theory, than the above procedure since it only requires dividing the net core-loss intensity images of two elements and correcting for the difference in cross-section (Cx/Cy = [Sx/Sy][(σy/(σx])- However, there are a few practical factors that must be considered in practice.