The basic SI unit of luminous intensity. The standard originally was based on the light emission of a candle flame, then as the glow from molten platinum, but then things got more complicated. In contemporary SI terms, the candela is the luminous intensity, in the perpendicular direction, of an area of 1 / 600,000 square meter of a blackbody radiator at the temperature of freezing platinum (2,045 Kelvin), under a pressure of 101,325 newtons per square meter. One candela emits 4 lumens of light flux. For more information, get a degree in electrical engineering or physics, just like the person who came up with this way too complicated, but delightfully precise, measurement. See also luminance and SI.