Equipping a transmission electron microscope with an energy-filter offers extraordinary advantages for the characterization of both materials science and biological samples. Besides improvements for TEM imaging and electron diffraction like better contrast and resolution, elemental mapping using inner-shell ionizations has become the main application of EFTEM. Elemental maps with resolution down to 1 nm and elemental sensitivities down to a single monolayer have been reported. Using a Philips CM20 equipped with a Gatan Imaging Filter (GIF) for our experimental work, we acquired elemental maps with the three window method (A.E ^-1 r background extrapolation from two pre-edge windows) and jump ratio images (division of post-edge image by a pre-edge image). One important application of EFTEM is the detection of secondary phases in materials e.g. precipitates and grain boundary phases. For example, fig.la shows the TEM-image of a 10%Cr steel with the secondary phases mostly invisible.