"The Sun never knew how great it was until it hit the side of a building." Louis Kahn
Architectural lighting design is a field within architecture, interior design and electrical engineering that is concerned with the design of lighting systems, including natural light, electric light, or both, to serve human needs.[1]
The design process takes account of:
- the kind of human activity for which lighting is to be provided.
- the amount of light required.
- the colour of the light as it may affect the views of particular objects and the environment as a whole.
- the distribution of light within the space to be lighted, whether indoor or outdoor.
- the effect of the lightened system itself on the user.
It is important to appreciate that the ultimate criterion of success in lighting is the human response, that is. whether what is to be seen clearly, easily and without discomfort." Lighting designers are often specialists who must understand the physics of light production and distribution, the physiology and psychology of light perception by humans, the anatomy of the human eye, and the response of the rods and cones to light.
Photometric Studies
Photometric studies (also sometimes referred to as "layouts" or "point by points") are often used to simulate lighting designs for projects before they are built or renovated. This enables architects, lighting designers, and engineers to determine whether a proposed lighting setup will deliver the amount of light intended. They will also be able to determine the contrast ratio between light and dark areas. In many cases these studies are referenced against IESNA orCIBSE recommended lighting practices for the type of application. Depending on the type of area, different design aspects may be emphasized for safety or practicality (i.e. such as maintaining uniform light levels, avoiding glare or highlighting certain areas). Specialized software is often used to create these, which typically combine the use of two-dimensional digital CAD drawings and lighting calculation software.
The color temperature of a light source is the temperature of an ideal black-body radiatorthat radiates light of comparable hue to that of the light source. Color temperature is a characteristic of visible light that has important applications in lighting, photography,videography, publishing, manufacturing, astrophysics, horticulture, and other fields. In practice, color temperature is only meaningful for light sources that do in fact correspond somewhat closely to the radiation of some black body, i.e., those on a line from reddish/orange via yellow and more or less white to blueish white; it does not make sense to speak of the color temperature of, e.g., a green or a purple light. Color temperature is conventionally stated in the unit of absolute temperature, the Kelvin, having the unit symbol K.
Categorizing different lighting
| Temperature | Source |
|---|---|
| 1,700 K | Match flame, low pressure sodium lamps (LPS/SOX) |
| 1,850 K | Candle flame, sunset/sunrise |
| 2,700–3,300 K | Incandescent lamps |
| 3,000 K | Soft (or Warm) White compact fluorescent lamps |
| 4,100–4,150 K | Moonlight[2] |
| 5,000 K | Horizon daylight |
| 5,000 K |
Tubular fluorescent lamps or
cool white/daylight compact fluorescent lamps (CFL) |
| 5,500–6,000 K | Vertical daylight, electronic flash |
| 6,200 K | Xenon short-arc lamp[3] |
| 6,500 K | Daylight, overcast |
| 6,500–10,500 K | LCD or CRT screen |
| 15,000–27,000 K | Clear blue poleward sky |
|
These temperatures are merely characteristic; considerable variation may be present. |
|
To the extent that a hot surface emits thermal radiation but is not an ideal black-body radiator, the color temperature of the light is not the actual temperature of the surface. An incandescent lamp's light is thermal radiation, and the bulb approximates an ideal black-body radiator, so its color temperature is essentially the temperature of the filament.
Many other light sources, such as fluorescent lamps, or LEDs (light emitting diodes) emit light primarily by processes other than thermal radiation. This means that the emitted radiation does not follow the form of a black-body spectrum. These sources are assigned what is known as a correlated color temperature (CCT). CCT is the color temperature of a black-body radiator which to human color perception most closely matches the light from the lamp. Because such an approximation is not required for incandescent light, the CCT for an incandescent light is simply its unadjusted temperature, derived from the comparison to a black-body radiator.
Concept of lighting design[edit]
Comprehensive lighting design requires consideration of the amount of functional light provided, the energy consumed, as well as the aesthetic impact supplied by the lighting system. Some buildings, like surgical centers and sports facilities, are primarily concerned with providing the appropriate amount of light for the associated task. Some buildings, like warehouses and office buildings, are primarily concerned with saving money through the energy efficiency of the lighting system. Other buildings, like casinos and theatres, are primarily concerned with enhancing the appearance and emotional impact of architecture through lighting systems. Therefore, it is important that the sciences of light production and luminaire photometrics are balanced with the artistic application of light as a medium in our built environment. These electrical lighting systems should also consider the impacts of, and ideally be integrated with, daylighting systems. Factors involved in lighting design are essentially the same as those discussed above in energy conservation analysis.
Architectural lighting design focuses on three fundamental aspects of the illumination of buildings or spaces. The first is the aesthetic appeal of a building, an aspect particularly important in the illumination of retail environments. Secondly, the ergonomic aspect: the measure of how much of a function the lighting plays. Thirdly is the energy efficiency issue to ensure that light is not wasted by over-illumination, either by illuminating vacant spaces unnecessarily or by providing more light than needed for the aesthetics or the task.
Each of these three aspects is looked at in considerable detail when the lighting designer is at work. In aesthetic appeal, the lighting designer attempts to raise the general attractiveness of the design, measure whether it should be subtly blended into the background or whether it should stand out, and assess what kind of emotions the lighting should evoke. The functional aspects of the project can encompass the need for the project to be visible (by night mostly, but also by day), the impact of daylight on the project and safety issues (glare, colour confusion etc.).
History of light fitting design
With the discovery of fire, the earliest form of artificial lighting used to illuminate an area werecampfires or torches. As early as 400,000 BCE, fire was kindled in the caves of Peking Man. Prehistoric people used primitive lamps to illuminate surroundings. These lamps were made from naturally occurring materials such as rocks, shells, horns and stones, were filled with grease, and had a fiber wick. Lamps typically used animal or vegetable fats as fuel. Hundreds of these lamps (hollow worked stones) have been found in the Lascaux caves in modern day France, dating to about 15,000 years ago. Oily animals (birds and fish) were also used as lamps after being threaded with a wick. Fireflies have been used as lighting sources. Candles and glass and pottery lamps were also invented.[11] Chandeliers were an early form of "light fixture".
Major reductions in the cost of lighting occurred with the discovery of whale oil and kerosene.[12] 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. The next major drop in price came about with theincandescent light bulb powered by electricity.[12]
Over time, electric lighting became ubiquitous in developed countries. Segmented sleep patterns disappeared, improved nighttime lighting made people made more activities possible at night, and morestreet lights reduced urban crime.Without light fittings there can be no Architectural Lighting Design. As these light sources change so does the practice of lighting Design.
