A boy holding up a sheet of black plastic. This image has a corresponding visible light image.  This plastic is opaque to visible light, but is transparent to far-infrared light.  This image was taken inthe far-infrared.  The different colors represent different temperatures on the object. The lightest colors are the hottest temperatures, while the darker colors represent a cooler temperature.  Thermography uses special cameras that can detect light in the far-infrared range of the electromagnetic spectrum (900?14,000 nanometers or 0.9?14 &micro;m) and creates an  image of the objects temperature..