The presence of light is rarely noted unless there is a perceived lack of it (dim atmosphere or shadows) or a perceived excess (glare). Like air, light is invisible and yet is everywhere in the visual environment, as we cannot see without it.
The application of light is lighting—not only the equipment that acts as the delivery system for light, but also where the equipment places light and with what color and intensity. Good lighting provides the right quantity of light and visual comfort; it draws attention; beautifies space and architecture; influences human interaction, mood and atmosphere; and promotes safety and security. Bad lighting can do the opposite. Light is generally considered a basic commodity and rightly so. However, because lighting so strongly influences how we perceive the visual world around us, lighting is a critical asset of both the built environment and the organization that occupies it.
Lighting design is the process of developing lighting that enables the safe, productive and enjoyable use of buildings and spaces. The complete process includes programming, schematic design, design development, contract documentation, bidding and negotiation, construction, and postoccupancy evaluation. Fundamentally, it involves identifying the lighting goals and selecting the correct combination of equipment and techniques that will satisfy these goals. This combination can vary from project to project, making lighting design a creative process that is often more art than science.
It begins with the “who” of lighting; who are the ultimate lighting users, how will they use the space, and what are their needs? Programming involves understanding task and space characteristics, noting any important features, materials, finishes, architecture and energy, and maintenance and safety issues.
The lighting concept follows from satisfying these needs. If the owner wants the lighting to make an office space appear public, bright and spacious, then the basic design concept might be, “a direct/indirect lighting system will be used to provide task illumination for users while illuminating upper walls and the ceiling to make the space appear bright and visually larger.” In a reception area attached to the office, another goal might be to attract visitor attention to the reception desk and a wall-mounted company logo behind it. In this case, the basic design concept might be, “light intensities on the reception desk and company logo artwork behind it will be at least three times higher than the general ambient lighting to attract occupant attention.”
The following concepts may require different lighting techniques and subsequent combination, or layering, of them in a space to create a variety of effects within a lighting composition.
Task lighting provides sufficient lighting levels for users to perform visual tasks. The lighting should be designed so that it provides sufficient maintained lighting levels for users to perform tasks at the desired degrees of speed, accuracy and safety, accounting for all light-loss factors that erode levels over time.
Task lighting may be part of the ambient illumination layer or localized lighting. Ambient lighting, also called general lighting, is usually provided by ceiling-mounted lighting equipment, and provides sufficient light primarily for the task of orientation (people walking around the space). As ambient lighting is usually diffused and uniform, it can be bland; for visual interest, accent or other lighting techniques can be used to create focal points or other interest. Task lighting is usually provided by ceiling-mounted equipment; localized equipment, such as portable or hardwired task lights; or a combination of the two; it provides sufficient lighting levels for performance of specific visual tasks.
Accent lighting is used to highlight key objects, displays, artwork, standout architectural features and special areas by making them significantly brighter than their surround. As the eye is attracted to points of brightness in the field of view, focal points and a visual hierarchy can be established. Highlighting areas, meanwhile, can be useful for wayfinding.
When an object is to be accented, we typically want to highlight the object only and avoid spill lighting on the surround, which would reduce the contrast we need. Therefore, focused, directional fixtures are often used to produce effective accent lighting, particularly when smaller objects are involved. Various lighting sources and fixtures offer a range of distributions from wide to pin spot, enabling a tight focus on even very small objects. Examples of lighting sources include halogen (low or line voltage), ceramic metal halide, compact fluorescent and light-emitting diode (LED). To make the object very bright, a sufficient “punch” is needed—a high level of intensity in the fixture’s center beam. Intense directional lighting will create shadows and result in strong texture, which can be emphasized using point-source lamps.
Accent illumination should make sense. For example, if a statue in a corner is moved, but the accent light is still operating, then we are drawing attention to an empty corner, which is visually confusing and distracting. For this reason, if the illuminated object is likely to be moved, it would be useful to have lighting fixtures that can be either reaimed or moved, such as track lighting or aimable downlights.
Framing is a type of accent lighting involving a recessed or surface-mounted framing projector with adjustable shutters, which provides precise focus on, for example, a painting on a wall. The effect is highly dramatic as the painting becomes very bright and its surround dark, resulting in high contrast and visual interest.
Downlighting places light on objects or surfaces below a lighting fixture that aims light downward. In some applications, downlights can be used to make a space appear smaller and more intimate. Intense, nondiffuse downlighting can be used to create an exciting atmosphere by producing high contrasts. It should be avoided, however, in spaces with critical prolonged tasks, as high contrasts are exciting but can be visually fatiguing over time. It should also be avoided in spaces where social communication is critical, as the shadowing produced by nondiffuse downlighting can render faces harshly.
Downlights do not need a uniform arrangement, but the arrangement should be organized and “make sense.” Higher mounting heights may require narrower beam spreads to avoid glare. Downlights placed close to a wall can produce tall and thin scalloping, which should generally be avoided unless desired for a particular aesthetic reason. Typical sources include compact fluorescent, ceramic metal halide and LEDs.
Uplighting places light on objects or surfaces above a lighting fixture that aims in an upward direction. Its effect is either very desirable or undesirable because it is unusual; effects range from the intimate to eerie. Uplighting with a simple candle can produce intimacy in a restaurant. Much landscape lighting includes uplighting to accentuate bushes and trees. This directional technique is also used to highlight architectural surfaces and details indoors and out, and ceilings and walls in indoor spaces.
Wall washing and grazing: Lighting on vertical surfaces can make a room appear more public and spacious, can articulate texture and can use room surfaces to increase lighting levels and perception of brightness.
Wall washing entails evenly illuminating a wall from top to bottom in a smooth graded wash, calling for a uniform distribution of intensity across its surface. Shadows on the surface are eliminated, hiding imperfections and flattening its visual appearance. Virtually any lighting source can be used. Typical wall-wash fixtures include track lighting and ceiling-mounted fixtures placed at a constant distance from the wall and each other. The fixtures must be placed at a sufficient distance from the wall to produce the washing effect. Fixture quality and placement are critical to producing uniform lighting.
Grazing is achieved by placing the lighting fixtures closer to the wall and thereby reducing the angle of light striking it, which produces shadowing and reveals texture. By changing the distance from the wall and resulting angle of light, different grazing effects can be achieved. Grazing is used to reveal interesting textured surfaces such as stone and brick—where texture is a sign of beauty, not imperfection.
Cove lighting uses perimeter coves to conceal lighting that projects a pleasing pattern on the ceiling and indirect light distribution, or ambient lighting, into the space. Cove lighting may use linear or point sources; while linear sources are economical, ensure that the fixtures are placed properly to create a seamless pattern by avoiding socket shadows. Avoid shadows by leveling up the tops of the lamp and cove.
Silhouetting: While rarely employed in commercial buildings, light can silhouette objects to create a striking display of a sculpture, logo or other object or architectural feature. Light striking the front of the object is softened or eliminated while light strikes the back of the object, rendering it in silhouette. The backlight could be intense or diffused depending on the clarity needed for the silhouette.
Sparkle and glitter or tiny points of glare, can create visual interest and contribute to an atmosphere of elegance. As with other lighting techniques, this must make sense with the environment; sparkle and glitter would look great in a high-end restaurant (sparkle on silverware in a restaurant, a chandelier, a fiber optic or LED “starry sky”), but would be confusing and distracting in a fast-food restaurant.
Visible equipment: Architectural lighting often involves using lighting to accentuate the architecture and space features rather than directly participating as architecture or a space feature. Lighting, however, can be used to make a direct statement either as a major focal point, supporting an architectural element or simply providing subtle visual cues about the space, its owner and its occupants.
Daylighting can affect people and spaces by providing sensory availability, a connection to nature, time/weather information, full-spectrum light and modeling. Also, an indirect lighting component produces wall- and ceiling-washing effects, which can provide a more pleasant and comfortable visual environment. When designing a lighting system, one must consider where daylight will enter the space and in what intensity, how it will be controlled, and how the electric lighting and daylighting will be integrated.
By understanding basic lighting techniques and how to layer them successfully, electrical contractors can help owners realize their lighting goals.
DILOUIE, a lighting industry journalist, analyst and marketing consultant, is principal of ZING Communications. He can be reached at www.zinginc.com.