Full-spectrum
Encyclopedia
Full-spectrum light is light that covers the electromagnetic spectrum
from infrared
through near-ultraviolet
, or all wavelengths that are useful to plant or animal life; in particular, sunlight
is considered full spectrum, even though the solar spectral distribution reaching Earth changes with time of day, latitude, and atmospheric conditions.
"Full-spectrum" is not a technical term when applied to an electrical light bulb but rather a marketing term implying that the product emulates natural light.
Products marketed as "full-spectrum" may produce light throughout the entire spectrum, but actually do not produce an even spectral distribution, and may not even differ substantially from lights not marketed as "full-spectrum".
and Color Rendering Index (CRI) are the standards for measuring light. There is no technical definition of "full-spectrum" so it cannot be measured. To compare "full-spectrum" sources requires direct comparison of spectral distributions.
A cube of carbon
"C" will radiate light of varying spectral power distribution
(SPD) as it is heated. At 0 K, it is pure black, while at about 5,000 K to 5,500 K, it appears similar to noon daylight.
by artist
s who paint
pictures on canvas when they paint at night
or inside (ideally, during the day the art studio should have north sunlight
, but many artists don't have access to north sunlight so they use full-spectrum lamps instead) in order to make sure that the colors they are using appear in their natural hue
as they will appear when the painting is displayed in a home
or in an art gallery
.
Full-spectrum lamps are also used by color scientists or color matchers in paint
stores to match colors at night or inside when they don't have access to north sunlight.
Some plants grow better when given more of a certain color light, due to the mechanism of photosynthesis
.
(SAD) through the use of "light boxes" that mimic natural sunlight
, which may not be available in some areas during the winter months. Light is an environmental stimulus for regulating circadian cycles.
Lightbox therapy, otherwise known as phototherapy, is a recognized modality for depression (such as SAD). It is also the primary treatment for circadian rhythm sleep disorder
s. Depending on the quality of the light, it is estimated that 10,000 lux
is needed for effective treatment. Not all light boxes are the same, and some produce only blue or green light.
A Cornell University
study reached mixed conclusions on the use of full-spectrum lighting in restaurants to promote sales.
The National Research Council of Canada Institute for Research in Construction, a Canadian government research and development agency, has published several scientific articles about full-spectrum lighting, collected on their web page. The authors of these papers also have concluded that full-spectrum lighting (~5000 K, CRI>90) does not confer any benefits on performance, mood, or health compared to typical cool-white fluorescent lighting.
Electromagnetic spectrum
The electromagnetic spectrum is the range of all possible frequencies of electromagnetic radiation. The "electromagnetic spectrum" of an object is the characteristic distribution of electromagnetic radiation emitted or absorbed by that particular object....
from infrared
Infrared
Infrared light is electromagnetic radiation with a wavelength longer than that of visible light, measured from the nominal edge of visible red light at 0.74 micrometres , and extending conventionally to 300 µm...
through near-ultraviolet
Ultraviolet
Ultraviolet light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays, in the range 10 nm to 400 nm, and energies from 3 eV to 124 eV...
, or all wavelengths that are useful to plant or animal life; in particular, sunlight
Sunlight
Sunlight, in the broad sense, is the total frequency spectrum of electromagnetic radiation given off by the Sun. On Earth, sunlight is filtered through the Earth's atmosphere, and solar radiation is obvious as daylight when the Sun is above the horizon.When the direct solar radiation is not blocked...
is considered full spectrum, even though the solar spectral distribution reaching Earth changes with time of day, latitude, and atmospheric conditions.
"Full-spectrum" is not a technical term when applied to an electrical light bulb but rather a marketing term implying that the product emulates natural light.
Products marketed as "full-spectrum" may produce light throughout the entire spectrum, but actually do not produce an even spectral distribution, and may not even differ substantially from lights not marketed as "full-spectrum".
Measurement
Color temperatureColor temperature
Color temperature is a characteristic of visible light that has important applications in lighting, photography, videography, publishing, manufacturing, astrophysics, and other fields. The color temperature of a light source is the temperature of an ideal black-body radiator that radiates light of...
and Color Rendering Index (CRI) are the standards for measuring light. There is no technical definition of "full-spectrum" so it cannot be measured. To compare "full-spectrum" sources requires direct comparison of spectral distributions.
Carbon
Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...
"C" will radiate light of varying spectral power distribution
Spectral power distribution
In color science and radiometry, a spectral power distribution describes the power per unit area per unit wavelength of an illumination , or more generally, the per-wavelength contribution to any radiometric quantity .Mathematically, for the spectral...
(SPD) as it is heated. At 0 K, it is pure black, while at about 5,000 K to 5,500 K, it appears similar to noon daylight.
Use in art and in color matching
Full-spectrum fluorescent lamps are used in the art studioStudio
A studio is an artist's or worker's workroom, or the catchall term for an artist and his or her employees who work within that studio. This can be for the purpose of architecture, painting, pottery , sculpture, scrapbooking, photography, graphic design, filmmaking, animation, radio or television...
by artist
Artist
An artist is a person engaged in one or more of any of a broad spectrum of activities related to creating art, practicing the arts and/or demonstrating an art. The common usage in both everyday speech and academic discourse is a practitioner in the visual arts only...
s who paint
Painting
Painting is the practice of applying paint, pigment, color or other medium to a surface . The application of the medium is commonly applied to the base with a brush but other objects can be used. In art, the term painting describes both the act and the result of the action. However, painting is...
pictures on canvas when they paint at night
Night
Night or nighttime is the period of time when the sun is below the horizon. This occurs after dusk. The opposite of night is day...
or inside (ideally, during the day the art studio should have north sunlight
Sunlight
Sunlight, in the broad sense, is the total frequency spectrum of electromagnetic radiation given off by the Sun. On Earth, sunlight is filtered through the Earth's atmosphere, and solar radiation is obvious as daylight when the Sun is above the horizon.When the direct solar radiation is not blocked...
, but many artists don't have access to north sunlight so they use full-spectrum lamps instead) in order to make sure that the colors they are using appear in their natural hue
Hue
Hue is one of the main properties of a color, defined technically , as "the degree to which a stimulus can be describedas similar to or different from stimuli that are described as red, green, blue, and yellow,"...
as they will appear when the painting is displayed in a home
Home
A home is a place of residence or refuge. When it refers to a building, it is usually a place in which an individual or a family can rest and store personal property. Most modern-day households contain sanitary facilities and a means of preparing food. Animals have their own homes as well, either...
or in an art gallery
Art gallery
An art gallery or art museum is a building or space for the exhibition of art, usually visual art.Museums can be public or private, but what distinguishes a museum is the ownership of a collection...
.
Full-spectrum lamps are also used by color scientists or color matchers in paint
Paint
Paint is any liquid, liquefiable, or mastic composition which after application to a substrate in a thin layer is converted to an opaque solid film. One may also consider the digital mimicry thereof...
stores to match colors at night or inside when they don't have access to north sunlight.
Use in gardening
Gardening under lights keeps plants blooming almost year-round, for a wintertime harvest.Some plants grow better when given more of a certain color light, due to the mechanism of photosynthesis
Photosynthesis
Photosynthesis is a chemical process that converts carbon dioxide into organic compounds, especially sugars, using the energy from sunlight. Photosynthesis occurs in plants, algae, and many species of bacteria, but not in archaea. Photosynthetic organisms are called photoautotrophs, since they can...
.
Use in seasonal affective disorder
In recent years, full-spectrum lighting has been used in the treatment of seasonal affective disorderSeasonal affective disorder
Seasonal affective disorder , also known as winter depression, winter blues, summer depression, summer blues, or seasonal depression, is a mood disorder in which people who have normal mental health throughout most of the year experience depressive symptoms in the winter or summer, spring or autumn...
(SAD) through the use of "light boxes" that mimic natural sunlight
Sunlight
Sunlight, in the broad sense, is the total frequency spectrum of electromagnetic radiation given off by the Sun. On Earth, sunlight is filtered through the Earth's atmosphere, and solar radiation is obvious as daylight when the Sun is above the horizon.When the direct solar radiation is not blocked...
, which may not be available in some areas during the winter months. Light is an environmental stimulus for regulating circadian cycles.
Lightbox therapy, otherwise known as phototherapy, is a recognized modality for depression (such as SAD). It is also the primary treatment for circadian rhythm sleep disorder
Circadian rhythm sleep disorder
Circadian rhythm sleep disorders are a family of sleep disorders affecting, among other things, the timing of sleep. People with circadian rhythm sleep disorders are unable to sleep and wake at the times required for normal work, school, and social needs. They are generally able to get enough sleep...
s. Depending on the quality of the light, it is estimated that 10,000 lux
Lux
The lux is the SI unit of illuminance and luminous emittance, measuring luminous flux per unit area. It is used in photometry as a measure of the intensity, as perceived by the human eye, of light that hits or passes through a surface...
is needed for effective treatment. Not all light boxes are the same, and some produce only blue or green light.
Independent verification
The non-profit Lighting Research Center, a group of utility companies, experts and government agencies, established the National Lighting Product Information Program (NLPIP) in the USA to provide objective information about the effectiveness of different lighting systems. According to the NLPIP, full-spectrum light does not provide any improved benefits over similar light systems.A Cornell University
Cornell University
Cornell University is an Ivy League university located in Ithaca, New York, United States. It is a private land-grant university, receiving annual funding from the State of New York for certain educational missions...
study reached mixed conclusions on the use of full-spectrum lighting in restaurants to promote sales.
The National Research Council of Canada Institute for Research in Construction, a Canadian government research and development agency, has published several scientific articles about full-spectrum lighting, collected on their web page. The authors of these papers also have concluded that full-spectrum lighting (~5000 K, CRI>90) does not confer any benefits on performance, mood, or health compared to typical cool-white fluorescent lighting.