Lux (lx) is defined as the illumination caused by a uniformly distributed luminous flux of 1 lumen (lm) incident on an area of 1m2, so: 1 lx = 1 lm / m2. An aliquot of a lux, a millilux, is called nox (nx). The name comes from the Latin nox = night. 1 nx = 0.001 lx = 1 mlx