Electron microscopes have electromagnetic lenses and special detectors that enable study of very small particles. A transmission electron microscope accelerates electrons in a vacuum until their wavelength is extremely short. A beam of these accelerated electrons is then aimed at a very thin paint sample (see the image to the right). Because the sample absorbs some electrons and transmits others (that is, allows them to pass through), the detector on the other side can create a detailed image of it, magnified up to about one million times. The technique makes it possible to study objects as small as a single atom.
This sample is approximately twelve microns thick, or twelve-thousandths of a millimetre. The electron microscope reveals that the large particles have a complex porous structure. The tiny, evenly distributed particles of white pigment come from the binding medium.