Principles of Lighting

• Lighting design determines how clearly colors appear in a room. Shana Novak/Photodisc/Getty Images

  Lighting can enhance or take away from the desired effect of a particular home interior design. Understanding basic lighting principles can help with selecting the correct quality of light for clear color rendering and making the most of lighting sources through the use of energy efficient bulbs.

Lighting Uses

• Different areas within a living space are often used to carry out various tasks. The type of lighting used in each area can vary depending on the type of task performed or on the type of effect desired, according to the U.S. Department of Energy. In general, ambient, task and accent lighting are three ways light is used within a living space. Ambient light acts as the general or primary source of illumination, while task lighting is designed to illuminate a particular area such as a desk or a reading chair. Accent lighting is used to direct attention to a special feature or aspect within a room, such as a mantel or a portrait. The overall effect from a lighting source also relies on the beam angle or spread emitted by the bulb, according to Forte Electric's reference pages. Beam angles appear as wide, narrow or normal in terms of how much area the light actually covers.

Light Quality

• Principles involving light quality refer to the temperature of the light and its ability to cast clear color tones, according to the U.S. Department of Energy. Light temperature has to do with how warm or cool a bulb's light rays appear. Warm light rays lean toward the yellow-red end of the color spectrum, while cool rays appear more bluish or white. Warm light is typically more suitable as an ambient lighting source, whereas areas in which visual tasks take place benefit more from cool light temperatures. Light temperature also affects how clearly colors are rendered within an area. Different bulb types often show a measurement for color rendition on the packaging. Measurements are made on a scale of 1 to 100 on a color rendition index, with 100 being the clearest possible rendition. Both temperature and rendition level can significantly affect how the colors in a room appear.

Energy Usage

• Energy usage refers to the amount of energy a bulb consumes versus the amount of illumination provided. The intensity of illumination for a particular bulb is measured in lumens. According to Forte Electric, lumens are based on the foot-candle, one of the original units of measurement. The amount of light reaching an object that sits 1 foot from a candle describes a foot-candle measurement. The lumen uses the same measuring standard. For example, a 100-watt incandescent bulb produces 1,750 lumens, meaning 1,750 foot-candles of illumination will reach any object sitting 1 foot away. In terms of ambient lighting needs, 30 to 50 lumens should suffice, while task light may require a bulb that produces 200 lumens or more, according to the U.S. Department of Energy. And while incandescent bulbs remain a popular standard, compact fluorescent (CFL) bulbs are significantly more energy-efficient, though color temperatures for CFLs can vary.