Etched plastic surface. Coloured scanning electron micrograph (SEM) of a plastic surface that has been etched with an argon ion beam. Argon atoms are ionised and then focused into a beam and directed at the surface in a vacuum. Argon is both an relatively inert chemical and a relatively heavy atom, and the impact of the argon ions erodes the target surface. This has produced the pattern seen here. This technique is used in semiconductor manufacturing to etch out the required circuits on a microchip. Magnification: x1100 when printed 10cm wide.