Desert Tan
06-03-2003, 12:54 PM
FYI: When talking about sunlight, tanning and burning, you often hear that there are 2 types of Ultraviolet (UV) light that the sun sends to us. UV-A and UV-B are the names of these 2 types of light. Although we call it light, it is not visible to our eyes because the wavelength of this UV light is so short that our eyes cannot perceive it.
The closest color to this wavelength that we can see is of a violet color and this is the reason that this light is called Ultraviolet. Because of the short wavelength, the waves of this light also have a high frequency and can emit alot of energy when they meet a surface that absorbs the light, and therefore, its energy. When it meets our skin the light (and its energy) is absorbed into the skin and chemical reactions will start with this energy. One of these reactions is the start of a chain of reactions that in the end will result in the forming of melanin, the natural pigment of the skin. This will give us a suntan and it is primarily caused by UV-A (for those interested: this light has a wavelength of 320-400 nanometers).
When the UV light that reaches the skin is of a shorter wavelength (like UV-B with a wavelength of 290-320 nanometers) it may not result in tanning, but because of the higher energy content of the light, it will primarily damage the skin leaving a redness known as erythema (sunburn). This is caused by UV-B and it also is this UV-B light that is primarily responsible for skin cancer. So the difference between UV-B and UV-A is not a difference in type of light, but only in wavelength and energy. The 2 wavelengths are so close that you may say that there is only a minimal difference between UV-B and UV-A. This made it very difficult to develop sunscreens that can be used in suntan lotions and will filter out the UV-B and will let pass the UV-A.
The science of suntanning has made great breakthroughs in the last 15 years and there are now several excellent suntan lotions on the market that provide effective protection against UV-B and still allow tanning.
--Mike
Salon Owner
The closest color to this wavelength that we can see is of a violet color and this is the reason that this light is called Ultraviolet. Because of the short wavelength, the waves of this light also have a high frequency and can emit alot of energy when they meet a surface that absorbs the light, and therefore, its energy. When it meets our skin the light (and its energy) is absorbed into the skin and chemical reactions will start with this energy. One of these reactions is the start of a chain of reactions that in the end will result in the forming of melanin, the natural pigment of the skin. This will give us a suntan and it is primarily caused by UV-A (for those interested: this light has a wavelength of 320-400 nanometers).
When the UV light that reaches the skin is of a shorter wavelength (like UV-B with a wavelength of 290-320 nanometers) it may not result in tanning, but because of the higher energy content of the light, it will primarily damage the skin leaving a redness known as erythema (sunburn). This is caused by UV-B and it also is this UV-B light that is primarily responsible for skin cancer. So the difference between UV-B and UV-A is not a difference in type of light, but only in wavelength and energy. The 2 wavelengths are so close that you may say that there is only a minimal difference between UV-B and UV-A. This made it very difficult to develop sunscreens that can be used in suntan lotions and will filter out the UV-B and will let pass the UV-A.
The science of suntanning has made great breakthroughs in the last 15 years and there are now several excellent suntan lotions on the market that provide effective protection against UV-B and still allow tanning.
--Mike
Salon Owner