Full Spectrum Lamps
Essay: Sunlight is the most critical element of virtually all forms of life.
Duro-Test Vita-Lite simulates natural light. Vita-Lite has a color rendering
index (CRI) of 91, sunlight has a CRI of 100.
Students had a 2.5
times better attendance record in rooms with broad spectrum lamps. That is they
were sick much less frequently. (Graves, 1985) (Hathaway, 1980)
The experiments and
research concludes that fluorescent lamps with superior color rendering result
in a visual clarity that is 40% greater than light from typical cool white
lamps.
The following
resource has been contributed to The Lighting Center by United Energy
Associates, The Certified Lighting and Power Quality Specialists.
Full Spectrum Lamps Essay
Research during the last ten years shows that the physiological and
psychological effects of artificial lighting are very significant and
quantifiable. The amount of light is important but the composition, of quality
of light, is perhaps the most important factor, affecting health, temperament,
and the ability to see clearly.
Sunlight is the most critical element of virtually all forms of life. The broad
spectrum lamps provided by United Energy are the closest approximation of
sunlight available in fluorescent lamps. The studies and reports summarized here
explain why it is so important to use natural sunlight type lighting wherever
possible.
All chemical, mineral and vitamin substances taken into the body have
unique-wavelength absorption characteristics. Wavelength energy penetrates the
skin and interacts directly at the molecular level with chemicals and minerals
in the blood supply, aiding in the substance breakdown for assimilation into the
body of the desirable substances and excretion of the undesirable. Broad
spectrum lamps and sunlight produce wavelengths that kill numerous bacteria,
molds, yeasts and viruses.
A most obvious example of this is that sunlight and broad spectrum fluorescent
light are used to treat jaundice. The short wavelengths of natural light
interact with serum bilirubin, converting it to a nontoxic substance. (McDonagh,
1980)
A study by the Council of Educational Facility Planners compared cool white to
broad spectrum fluorescent lamps in a controlled scientific test in classrooms.
Students had a 2.5 times better attendance record in rooms with broad spectrum
lamps. That is they were sick much less frequently. (Graves, 1985) (Hathaway,
1980)
Physiological studies have also conclusively shown that, under broad spectrum
lamps versus cool white lamps, humans have increased oxygen intake, reduced
heart rate, increased ability to absorb vitamin D and calcium and improved
muscle utilization. (Hughes, 1986) (Neer, 1984)
Natural sunlight makes people feel better than artificial light does. The more
natural the light the more comfort and better performance. Statistically
significant differences are proven for subjects in rooms lit by cool white lamps
versus broad spectrum lamps. Subjects brought from outdoors into cool white
rooms tended to become less lively or lethargic. The subjects exhibited no
change when brought from outdoors into broad spectrum rooms. Visual accuracy and
alertness were measurably better in the broad spectrum rooms versus the cool
white rooms. (Maas, 1974)
Recent reports conclude, "The results support the conclusion that
artificial lighting simulating natural light (broad spectrum lamps) is perceived
as significantly more pleasant, natural, bright and stimulating. Subjects felt
more relaxed, less fatigued and as having greater eye comfort under the
simulated natural light. Additionally, they rated their work as being more
distinct, easier and satisfying." (Hughes, 1986)
Being able to see clearly is typically attributed to the amount of light,
however, clear color rendering is at least as important. The most obvious
example of this is white appearing as white and black as black, instead of light
yellow and dark brown. Enhanced black and white contrast makes written material
easier to read and makes objects appear brighter.
Initial experiments by Aston and Bellchambers were confirmed by extensive
research by the Naval Submarine Research Laboratory. The experiments and
research concludes that fluorescent lamps with superior color rendering result
in a visual clarity that is 40% greater than light from typical cool white
lamps. The reason for this is that the red/green contrasts contribute to
distinguish borders and the blue/yellow make little or no contribution to the
distinctness of borders. Cool white lamps are strong in the blue/yellow
contrasts and weak in the red/green. Broad spectrum lamps have an appropriate
balance of spectral contrast. (Worthy, 1985)
FOR MORE INFORMATION
1. Birren, F.; Light, "Color and Environment"; 1969.
2. Boyce, P.R.; "Human Factors in Lighting"; 1981.
3. Graves, B.; "Shedding Light on Learning"; American School and
University; Volume 36; March 1985.
4. Hollowich, F.; "The Influence of Ocular Light Perception on Metabolism
in Man and Animals"; Springer Verlag; 1980.
5. Hughes, P. , Ph.D. ; "The Use of Simulated Natural Light in the Design
of the Earth Sheltered Environment"; Conference on Earth Sheltered
Environment/University of Minnesota; 1986.
6. Mass, J.; "Effects of Spectral Differences in Illumination on
Fatigue"; Journal of Applied Psychology, Volume 59; 1974.
7. Ott, J.; "Light Radiation and You"; 1982.
8. Tiller, D.; "Toward a Deeper Understanding of Psychological Aspects of
Lighting"; Journal of IES; Summer, 1990.
9. Worthey; "An Analytical Visual Clarity Experiment"; Journal of IES,
Fall 1985.
10. Wurtman, R.; "Biological Implications of Artificial Illumination";
IES National Technical Conference; September 1968.
