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Measuring Light Energy Wavelengths |
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The diagram shows the electromagnetic spectrum measured in nanometers starting at the low end of the scale with very short high-energy wavelenghts. These short wavelenghts are the ones which represent voice and power audio waves for AM and FM radio and microwaves. |
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Included in the powerful, short wavelenght band are the invisible and more energetic, ultraviolet rays. These are three types of ultraviolet rays: UV-A (320 to 380 nanometers), UV-B (290 to 320 nanometers) and UV-C (100 to 290 nanometers). The earth's atmosphere and ozone layer filter out most UV-C and a percentage of UV-B rays. UV-B causes sunburn, and prolonged exposured to it over many years has been linked to skin cancer. However, from recent atmospheric studies. scientists are concerned about the earth's ozone level, which at times shows signs of being depleted. This is likely to result in far more UV radiation reaching the surface of the Earth and may result in a greatly increased incidence of skin cancer. According to the American Cancer Society, there are about 17,300 new cases of melanoma carcinoma and about 800,000 basal and squamous cell skin cancers annually. There are about 2,100 melanoma skin cancer deaths per year. |
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That is considered as the visible band of the solar spectrum runs from roughly 380 nanometers to 780 nanometers. This is the only part of the spectrum visible to the naked eye. Above 780 nanometers come other invisible rays that we cannot see, but can only feel as heat. These are called infrared rays. |
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Visible and Invisible Ligt and Solar Heat |
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Roughly 44% of the sun's radiant energy is received by the earth in the form of visible light. Invisible light in the form of infrared solar heat accounts for another 53% of the sun's rays, with ultraviolet radiation making up the final 3%. Solar control window films are designed to reflect infrared heat waves and filter out most ultraviolet radiation. |
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Solar Radiation |
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Some Fact About Fading |
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It is generally accepted that UV radiation can be responsible for roughly 40%-60% of all fading. In addition to UV radiation, other factors that cause fading include: |
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1. Normal sunlight |
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2. Humidity/Moisture |
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3. Poor dye fastness of the material |
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4. Chemical vapors in the air |
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Facts About Fading |
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What Causes Fading? "As A Rule Of Thumb" |
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