One-billionth of a meter. Wavelengths of electromagnetic energy, which includes visible light, is measured in nanometers.

Irregularly shaped patterns, similar to oil on the surface of water, that appear in a color separation. They are caused by the varying amounts of air between the scanning cylinder and transparency surfaces as they come into contact. The light refracts into a rainbow pattern as it passes from the cylinder through the air pockets to the transparency. This is avoided by applying a coat of oil (to make airless contact) or a thin mist of powder (to prevent any contact) between the two surfaces.

A light blue color often used to make crop marks or notes on mechanicals. Also called nonphoto blue.