Posted at Saturday, October 28 2017 15:42:47 by Nichole Aragon for Lighting Fixtures
The more transparent the lighting fixture is, the higher efficacy. Shading the light will normally decrease efficiency but increase the directionality and the visual comfort probability.
The PH-lamps are a series of light fixtures designed by Danish designer and writer Poul Henningsen from 1926 onwards. The lamp is designed with multiple concentric shades to eliminate visual glare, only emitting reflected light, obscuring the light source.
An important property of light fixtures is the luminous efficacy or wall-plug efficiency, meaning the amount of usable light emanating from the fixture per used energy, usually measured in lumen per watt. A fixture using replaceable light sources can also have its efficiency quoted as the percentage of light passed from the "bulb" to the surroundings.
Major reductions in the cost of lighting occurred with the discovery of whale oil and kerosene. The potential of electric light as a new building material was recognized in the 1920s and became a useful design tool by the mid-century. Skillful lighting allowed for theatricality, narrative, and a new emphasis on structure and space. Gas lighting was economical enough to power street lights in major cities starting in the early 1800s, and was also used in some commercial buildings and in the homes of wealthy people. The gas mantle boosted the luminosity of utility lighting and of kerosene lanterns.