Full Spectrum Lighting

A quality full spectrum light source should not only duplicate the visible wavelengths of our sun,but should also offer high clarity and a spectrum balanced between all of the visible wavelengths. The standard definition of full spectrum lighting is a color rendering index (CRI) of 90 or higher and a correlated color temperature of 5000-6000 kelvin. The higher the CRI number the more pronounced color differences will be, increasing the clarity of ojects and the area illuminated by the lighting source. Pure sunlight at noon has a color temperature of around 5000 kelvin and water vapor in the atmosphere or cloudiness tending to make it closer to 6000 kelvin on an average day. Lamps producing color temperatures below 5000 kelvin will appear yellow to the user and include bulbs such as incandescent, standard fluorescent tubes, halogen bulbs, and high pressure sodium HID lamps. Lamps rated with a color temperature above 6,000 kelvin will appear more blueish in comparison to a natural lighting or quality artificial full spectrum lighting. Lamps with this blue appearance, such as the common daylight bulbs sold in retail outlets tend to make colors look rather "washed out" in comparison to the light produced by a true full spectrum light bulb.

Full spectrum light bulbs should not contain ultraviolet (UV) light of any kind. A few minutes outdoors under sunlight is able to supply your body with its UV needs for a day so there is no need to increase exposure to harmful UV rays with your artificial lighting source. UV radiation can be both harmful to your skin (skin cancer) , but can also cause damage to the eyes with long term exposure. Typically, bulbs marketed as full spectrum that include UV are the results of poor manufacturing processes. UV radiation produced by the cathode are not being fully absorbed by the phosphors in the bulb. High quality bulb manufacturers will insure that there are sufficient phosphors within their bulbs to convert all UV energy into visible light. There are also manufacturers that take matters one step futher by producing low mercury content full spectrum light bulbs that prevent UV exposure and also make the bulbs TCLP compliant for easy disposal and environmental friendliness.

There are new technologically advanced fluorescent bulbs arriving on the market that are taking full spectrum lighting beyond the old 70 year old technology used in most bulb manufacturing processes. Until recently there have been very few improvements to the tri-phosphor blend that has produced standard full spectrum lights since the 1930's. This new technology includes several new phosphors and a special manufacturing process creating what is known as scotopically enhanced full spectrum light. The outcome of this technology has created bulbs with a very high CRI of 96+ and a color temperature that matches natural sunlight. Scotopic enhancement takes advantage of how the human eye reacts to different light spectrums. Our vision is created by photons of light striking the retina of the eye that contains both rods and cones. An oversimplified approach tells us that the cones see in color while the smaller and more numerous rods see in shades of gray and allow for night vision. While this is true to a point, the rod/cone system actually act together with the rods controlling pupil size under all levels of lighting. Standard lighting practice has been to focus on strictly the photopic side of light, or lighting that targets the cones. By ignoring the role that the rods play in daytime vision and pupil size, typical indoor lighting creates glare at even moderate lighting levels. The new scotopically enhanced light bulbs include the extra phosphors needed to target both the rods and cones resulting in smaller pupil size and better visual acuity without any glare. A recent workplace study has shown that this approach to lighting was able to increase the visual acuity of healthy young workers by a factor significant enough to be similar to the difference of needing glasses versus not needing glasses. This new lighting technology holds great promise as we continue to move toward a society of indwellers spending more time at work and indoors. Workplaces can increase employee performance and reduce errors through this improved lighting and our children in schools will no longer have to tolerate the flickering yellow light of standard fluorescent lighting of old. For more information on scotopically enhanced full spectrum lighting please contact Full Spectrum Solutions, Inc. www.fullspectrumsolutions.com which is a manufacturer and affiliate member of the University of California at Davis Lighting TechnologyCenter www.cltc.ucdavis.edu.