Architectural lighting design is a field of work or study concerned with the design of lighting systems within the built environment, both interior and exterior. It can include the manipulation and design of daylight, electric light, or both, to serve human needs. Lighting design is grounded in both science and the visual arts. The basic aim of lighting within the built environment is to enable occupants to see clearly and comfortably. The objective of architectural lighting design is to balance the art and science of lighting to create mood and visual interest, and to enhance the experience of a space or place while still meeting technical and safety requirements.
Overview
The purpose of architectural lighting design is to balance the characteristics of light within a space to optimize the technical, visual, and, most recently, the non-visual components of ergonomics with respect to the illumination of buildings and spaces.
The technical requirements include the amount of light needed to perform a task, the energy consumed by the lighting within a space and the relative distribution and direction of light so as not to cause unnecessary glare or discomfort. The visual aspects of light are those concerned with the aesthetics and narrative of the space (e.g. the mood of a restaurant, the experience of an exhibition in a museum, the promotion of goods within a retail space, the reinforcement of a corporate brand) while the non-visual aspects are concerned with human health and well-being.
As part of the lighting design process, both cultural and contextual factors also need to be considered. For example, bright lighting was a mark of wealth through much of Chinese history, but uncontrolled bright light is known to be detrimental to insects, birds, and the visibility of stars.
History The history of electric light is well documented, and with the developments in lighting technology the profession of lighting developed alongside it. The development of high-efficiency, low-cost fluorescent lamps led to a reliance on electric light and a uniform blanket approach to lighting, but the energy crisis of the 1970s required more design consideration and reinvigorated the use of daylight.
The New York-based Illuminating Engineering Society (IES) was formed in 1906. A London-based organization established in 1909 with the same name is now known as the Society of Light and Lighting (SLL), a part of CIBSE. The International Commission on Illumination (CIE) was established in 1913. The Institution of Lighting Professionals was established as the Association of Public Lighting Engineers in 1924. Around the world similar professional organizations evolved.
Initially, these industry organizations were primarily focused on the science and engineering of lighting rather than the aesthetic design, but in 1969 a group of designers established the International Association of Lighting Designers (IALD). Other associations purely for lighting design have included the Professional Lighting Designers' Association (PLDA) established in 1994, the Association de Concepteurs Eclairage (ACE) in France established 1995, the Associazione Professionisti dell'Illuminazione (APIL) in Italy established in 1998, the Associação Brasileira de Arquitetos de Iluminação in Brazil in 1999 and the Professional Association of Lighting Designers in Spain (APDI) established in 2008.
As a profession
Architectural lighting designer is a stand-alone profession that sits alongside the professions of architecture, interior design, landscape architecture and electrical engineering.
One of the earliest proponents of architectural lighting design was Richard Kelly who established his practice in 1935. Kelly developed an approach to architectural lighting that is still used today, based on the perception of three visual elements as presented in a 1952 joint meeting of The American Institute of Architects, the American Society of Industrial Designers (now the Industrial Designers Society of America), and the Illuminating Engineering Society of North America, in Cleveland.
Education While many architectural lighting designers have a background in electrical engineering, architectural engineering, architecture, or luminaire manufacturing, several universities and technical schools now offer degree programs specifically in architectural lighting design.
Process The process of architectural lighting design generally follows the architect's plan of works in terms of key project stages: feasibility, concept, detail, construction documentation, site supervision and commissioning.
After the feasibility stage, where the parameters for the project are set, the concept stage is when the lighting design is developed in terms of lit effect, technical lighting targets and overall visual strategy usually using concept sketches, renderings, or mood boards.
Day lighting The source for daylight or natural lighting is the sun. Sunlight provides the greatest quality of light, rated 100 CRI, on the electromagnetic spectrum. There are psychological and physical health benefits that come from using daylight in a space. For example, it can help to ease seasonal affective disorder (SAD), it can provide people with the necessary vitamin D, and can assist in regulating circadian rhythms, or daily light and dark cycles. Using daylight as a light source can eliminate the use of energy. Daylighting can also cause deterioration of materials and finishes and an increased use of energy for cooling a space. The architectural makeup of a space impacts the day lighting. It can be used in a space through windows, openings of the interior, skylights, and reflective surfaces.
Electric lighting Electric lighting or artificial lighting is a type of architectural lighting that includes electric light sources. The overall purpose of electric lighting is to allow the user of the space to see at various times in the day, but especially at night or in winter season, when daylight is no longer a possible or sufficient source of light. Artificial lighting helps to create or enhance the aesthetic of a space. Various techniques can be implemented when it comes to electric lighting, since users have more control over the light. This can include dimming or increasing the brightness of a lamp, diffusion of the light source, and the use of different lamp hues. The main sources used for electric lighting include incandescent lamps, solid state lamps (LED, etc.), and gas discharge lamps.
Fixtures
Lighting fixtures come in a wide variety of styles for various functions. The most important functions are as a holder for the light source, to provide directed light and to avoid visual glare. 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 excess heat and is in keeping with safety codes.
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. 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.
Lighting design layers Designers utilize the idea of lighting layers when creating a lighting plan for a space. Lighting layers include: task layer, focal layer, ambient layer, decorative layer, and daylight layer. Each layer contributes a function to the space and often they work together to create a well composed lighting design. The task layer is lighting that serves a purpose to perform a certain job or task. Typically, in this layer, there tends to be a need for more light. An example of this would be the use of under cabinet lighting in a kitchen. The focal layer is when lighting is used to highlight a certain feature in a room, such as a fireplace. This type of lighting draws the eye to that certain area. The ambient layer provides for background or general lighting. This layer has a strong influence on the brightness of a space. In the decorative layer, lighting is used as an ornament to the space and can help develop the style. The daylight layer uses natural light or the sun to light a space. Using the layering technique helps to develop the aesthetic and functionality of lighting.
Photometric studies
Photometric studies are performed 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 layout 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 or CIBSE 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). A specialized lighting design application is often used to create these, which typically combine the use of two-dimensional digital CAD drawings and lighting simulation software.
Color temperature for white light sources also affects their use for certain applications. The color temperature of a white light source is the temperature in kelvin of a theoretical black body emitter that most closely matches the spectral characteristics of the lamp. Incandescent light bulbs have a color temperature around 2700 to 3000 kelvin; daylight is around 6500 kelvin. Lower color temperature lamps have relatively more energy in the yellow and red part of the visible spectrum, while high color temperatures correspond to lamps with more of a blue-white appearance. For critical inspection or color matching tasks, or for retail displays of food and clothing, the color temperature of the lamps will be selected for the best overall lighting effect. Color may also be used for functional reasons. For example, blue light makes it difficult to see veins and thus may be used to discourage drug use.
Correlated color temperature Temperature Source 1,700 K Match flame, low-pressure sodium lamps (LPS/SOX) 1,850 K Candle flame, sunrise, sunset 2,700–3,300 K Incandescent lamps, soft-white fluorescent lamps 3,000 K Warm-white fluorescent lamps 4,100–4,150 K Moonlight, cool-white fluorescent lamps 5,000 K Horizon daylight 5,500–6,000 K Vertical daylight, electronic flash 6,200 K Xenon short-arc lamp 6,500 K Daylight, overcast, daylight fluorescent lamps 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.