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.