A question on the Microscopy Listserver concerned using an FESEM to examine a thin, thermally-evaporated gold film on single crystal germanium. It is always a difficult problem to find small surface details or textures on a smooth surface in the SEM. A surface without visible topography looks the same whether it is in or out of focus, and so the method to make sure the surface is in focus is a slow, iterative one.

My researchers like to give me a one inch square of highly polished steel or titanium and ask me to find and analyze the five tiny inclusions somewhere in the middle. If there is a particular feature or area that I need to examine, I find that area by eye or under a low power, binocular light microscope and mark it with a fine, red felt-tip pen.