Lighting includes both artificial light sources such as lamps and natural illumination of interiors from daylight. Lighting represents a major component of energy consumption, accounting for a significant part of all energy consumed worldwide.

Artificial lighting is provided today by electric lights, but previously by Gas lighting, candles or oil lamps. Proper lighting can enhance task performance or aesthetics, while there can be energy wastage and adverse health effects of lighting. Indoor lighting is a form of fixture or furnishing, and a key part of interior design. Lighting can also be an intrinsic component of landscaping.

Fixtures

Light fixture

Lighting fixtures come in a wide variety of styles for various functions. Some are very plain and functional, while some are pieces of art in themselves. Nearly any material can be used, so long as it can tolerate the heat and is in keeping with safety codes.

Proper selection of fixtures is complicated by the requirement to minimize the veiling reflections off of printed material. Since the exact orientation of printed material may not be closed controlled, a visual comfort probability can be calculated for a given set of lighting fixtures.

Types

Lighting types are classified by intended use as general, localized, or task lighting, depending largely on the distribution of the light produced by the fixture.

• General lighting fills in between the two and is intended for general illumination of an area. Indoors, this would be a basic lamp on a table or floor, or a fixture on the ceiling. Outdoors, general lighting for a parking lot may be as low as 10-20 lux since pedestrians and motorists already used to the dark will need little light for crossing the area.

• Task lighting is mainly functional and is usually the most concentrated, for purposes such as reading or inspection of materials. For example, reading poor-quality reproductions may require task lighting levels up to 1500 lux and some inspection tasks or surgical procedures require even higher levels.

• Accent lighting is mainly decorative, intended to highlight pictures, plants, or other elements of interior design or landscaping.