Thermogram of a man sunbathing. Thermograms show the emission of infrared radiation, displaying it as colour-coded surface temperatures. The range shown is from 23 degrees Celsius (purple), through blue, green and yellow, up to 35 degrees Celsius (red). The man's face and neck are absorbing the Sun's heat and are very hot. In comparison, the sunglasses and vest, which are reflecting the Sun, are much cooler.