UV Light

UVA – has long wave lengths, referred to what is commonly knows as “black light”
UVB – midrange wavelengths that cause sunburns
UVC – short wave lengths effective in microbial control 

UVA, otherwise known as a black light has several uses.  The black light emits long wave UV light and very little visible light giving it its special quality.  Fluorescent black lights are made in a similar way that ordinary fluorescent lights are made, except only one phosphor is used and a deep bluish purple glass called Wood’s glass replaces the clear glass envelope used in the bulb.  The Wood’s glass removes visible components of light beams leaving only invisible radiation.  Because of this invisible radiation, governments can then identify, or mark, special documents such as credit cards, passports, or driver’s licenses with a UV watermark.  This watermark is only visible under the black light and can help authenticate documents as well as bank notes.  This special black light is also used in forensic investigations to trace any blood, urine, or saliva that is otherwise invisible to the naked eye. This black light is commonly found in bug zappers, as the UV fluorescent light is used to attract insects.  The black light is also commonly used in a teenager’s room.  Because this light emits long wavelengths and very little visible light, it tends to illuminate white, or light colored items making them even brighter. 

The other form of UV light, such as UVC is used as microbial control.  Because of the short wavelengths UVC can eliminate micro bacteria and micro organisms.  Some plants are considering the use of UVC to treat apple juice or apple cider instead of pasteurizing and fermenting the juices and ciders.  By using the light it will reduce, and possibly eliminate, organisms and bacteria from the juices.  However this process has not been approved, and is still being researched.

The sun emits all bands of UV light; however the two that affect us the most are the UVA and UVB.  UVA is believed to be the cause of wrinkles.  This light penetrates deep into our skin causing damage to our DNA and our cells contributing to the aging of our skin, causing long-term damage.  UVB is the light that causes sunburns this is the light that causes immediate danger to our skin; it is this UV light that is believed to be the link to skin cancer.  So be careful when you step outside.  Make sure that your sunblock is properly covering you from all UV rays of light.