Full spectrum lighting
The term full-spectrum is not a technical term, but rather a marketing term implying a smooth and continuous spectral power distribution (SPD) without the spikes and troughs in radiant energy common with most discharge light sources such as fluorescent and metal halide. Full-spectrum products are usually marketed as electric light sources that emulate natural daylight; the explicit or implicit message is that "natural" daylight is always better than "artificial" electric light. Some full-spectrum light sources are also marketed as emitting ultraviolet (UV) radiation, as well as visible light. Historically, it has been used in artistic environments for determining correct color perception. Painters, graphic designers, and decorators have been using full spectrum lamps for decades to ensure perfect color matching. Over the years, people noticed that not only did this type of light allow them to see colors better, but they were also often able to see details more clearly. Proponents of full spectrum lighting say that it also reduces glare, increases productivity, operates cooler, and increases feelings of well being due to the simulation of natural sunlight. In fact, some health professionals use it to treat a condition known as Seasonal Affective Disorder (SAD). Light bulbs are typically classified as "full spectrum" when they have a CRI (Color Rendering Index) above 90 and a Kelvin temperature around 5500K. Most full-spectrum light sources are marketed at a premium price over other light sources, and they generally produce fewer lumens per watt than comparable light sources. If valid, the benefits claimed for full-spectrum light sources would seem to be well worth the additional expense and the loss in efficacy. But with each manufacturer making up its own definition of full-spectrum lighting, consumers have no way to know exactly what they are getting or what benefits to actually expect. Independent Verification: "Full-spectrum light sources and health. Full-spectrum light sources will not provide better health than most other electric light sources. Recent research has shown that human daily activities are strongly influenced by the solar light/dark cycle. The most notable of these daily, or circadian, cycles is the sleep/wake cycle; but other activities including mental awareness, mood, and perhaps even the effectiveness of the immune system go through regular daily patterns. Light is the most important environmental stimulus for regulating these circadian cycles and synchronizing them to the solar day. Short wavelength (blue) light is particularly effective at regulating the circadian system; long wavelength (red) light is apparently inconsequential to the circadian system. Thus, to maximize efficiency in affecting the circadian system, a light source should not mimic a full spectrum, but instead should maximize only short wavelengths. Even if a full-spectrum light source includes short wavelength light in its spectrum, it will not necessarily ensure proper circadian regulation because, in addition, the proper intensity, timing and duration of the light exposure are all equally important for satisfactory circadian regulation (Rea et. al, 2002). Light therapy treatment of seasonal affective disorder (SAD) usually involves regulated exposure to a white light source, commonly 10,000 lux at the eye for 30 minutes per day (Partonen and Lönnqvist, 1998). Any white light source will be effective at these levels (Lam and Levitt, 1999), so full-spectrum light sources are in no way special for treatment of SAD." Back : Home and Outdoor lighting Home : Cleaning Guide |