Light_Vocabulary

__Floodlight __: A luminaries used to light a scene or object to a level much brighter than its surroundings. __Lens __: A transparent or semi-transparent element which controls the distribution of light by redirecting individual rays. __Ambient Lighting __: The general lighting present in an area --excluding task lighting and accent lighting but including general lighting and daylight streaming in. __Illuminance:__ The "density" of light (lumens/area) incident on a surface; i.e. the light level on a surface. Illuminance is measured in footcandles or lux.

__Light Pollution: __Light that is directed to areas where it is not needed, and thereby interferes with some visual act. Light pollution directed or reflected into the sky creates a "dome" of wasted light and makes it difficult to see stars above cities. __Light Trespass (Spill Light): __Light that is not aimed properly or shielded effectively can spill out at into areas that don't want it: it can be directed towards drivers, pedestrians or neighbors. It is distracting and annoying and can sometimes be disabling.