Light+Vocabulary

**Accent Lighting**: lighting that is used to accent or highlight a particular object such as a work of art. To be effective accent lighting should be approximately four or five times the level of ambient light in the room, area, or space. House plants can be accented by aiming an uplight at the wall behind the plant, creating a dramatic silhouette of the plant against the wall.


 * Ballast :** an electrical device used with fluorescent and HID (high intensity discharge) lamps (light bulbs) to supply sufficient voltage to start and operate the lamp but then to limit the current during operation.


 * Floodlight: ** a broad-beamed high intensity artificial light source.


 * Sky Glow: ** also, known as "light pollution". The "haze" or "glow" that surrounds highly populated areas and reduces the ability to view the nighttime sky. Specifically, light that enters the sky from an outdoor lighting system by indirect light reflected from atmospheric particles such as fog, dust, or smog.


 * Troffer: ** a long, recessed lighting unit, usually installed in an opening in the ceiling.


 * Quartz: ** a name for fused silica or melted sand from which many high-temperature containers are fashioned in the lighting industry. [[image:th_18923.jpg width="307" height="195" align="right"]] Quartz looks like glass but can withstand the high temperatures needed to contain high intensity arc discharges.


 * Wattage Indicator Reduced: ** indicates that this is a reduced wattage option for lamps normally used in this application. Be sure to check wattage, lumens and life to determine which lamp is best suited to your needs.


 * Work Plane: ** the horizontal plane (a flat surface) on which a visual task (such as reading or writing) is performed. Illumination is designed for this plane, which is normally the height of a standard table (approximately 30 inches from the floor).