Orientation Imaging Microscopy, OIM, is a relatively new technique which provides an image of the surface of polycrystalline material in which the grains are distinguished by their orientation differences, by the strain within them and the type of grain boundaries that separate them. The technique evolved from the work of Dingley and Venables on application of electron backscatter diffraction EBSD in the scanning electron microscope. In OIM, electron backscatter diffraction patterns are obtained successively at regularly spaced points on a sample surface. At each point, the diffraction pattern is captured, transferred to a computer and automatically indexed. Crystal orientation and diffraction line width are measured. Recent advances have been concerned with post data collection image processing.In the following illustration orientation imaging microscopy was used to investigate the microstructure of submicron aluminium, vapour deposited onto single crystal silicon coated with silicon dioxide. The experimental procedure described in reference 2 was adapted using a Philips XL 30 SEM fitted with a tungsten electron gun.