Sunday, February 24, 2013

Blacklight Basics

Blacklights emit light in the ultraviolet (UV) spectrum to make anything fluorescent glow brightly without emitting much visible light.  For blacklight volleyball, this allows you to control what is glowing.  By using fluorescent balls, court lines, and uniforms, you can create an amazing glow volleyball experience.

 

Types of Blacklights:
·      Fluorescent tubes: 

Often found in 48", 24", and 18" varieties, these are basically fluorescent lamps with a different sort of phosphor coating. This coating absorbs harmful shortwave UV-B and UV-C light and emits UV-A light (in the same basic way the phosphor in a fluorescent lamp absorbs UV light and emits visible light). The "black" glass tube itself blocks most visible light, so in the end only benign long-wave UV-A light, along with some blue and violet visible light, passes through.

Pros: Ubiquitous and you may already own them

Cons: Weak light and limited range means you may need many of these to cover a volleyball court.  Also, the lights need to screw into a ballast (fixture).  The lights are easily breakable and can be very difficult to store for reuse.

·     Incandescent Light Bulbs:

An incandescent black light bulb is similar to a normal household light bulb, but it uses light filters to absorb the light from the heated filament. It absorbs everything except the infrared and UV-A light (and a little bit of visible light.

Pros: They technically can make things glow

Cons: These are the weakest of blacklights.  They are unable to project more than a few feet and are a poor choice for volleyball or other large events. 


·         Mercury Vapor Bulbs:

Mercury Vapor black light lamps are made in power ratings of 100 to 1000 watts. These do not use phosphors, but rely on the intensified and slightly broadened 350–375 nm spectral line of mercury from high pressure discharge at between 5 and 10 standard atmospheres (500 and 1,000 kPa), depending upon the specific type. These lamps use envelopes of Wood's glass or similar optical filter coatings to block out all the visible light and also the short wavelength (UVC) lines of mercury at 184.4 and 253.7 nm, which are harmful to the eyes and skin. A few other spectral lines, falling within the pass band of the Wood's glass between 300 and 400 nm, contribute to the output. These lamps are used mainly for theatrical purposes and concert displays. They are more efficient UVA producers per unit of power consumption than fluorescent tubes.

Pros: These can be powerful units and project a long distance

Cons: Bulbs are breakable. The fixtures tend to be bulky and very heavy. The units will get extremely hot during use and have to have cool down periods between uses. The bulbs take a while to warm up to full power. Risk of bulbs blowing during event


·         LED:

LED blacklights are the newest type of unit on the market.  Using solid state LED's that put out the specific blacklight frequency, they do not need filters to achieve their effect.  Certain LED fixtures can be extremely powerful and shoot from one side of your volleyball court to the other.  They are the ideal choice for a black light volleyball tournament. 

Pros: Lightweight, instant-on, no bulbs to break, cool to the touch, low power consumption, no additional fixture needed.

 

Harris, Tom.  "How Black Lights Work"  18 July 2002.  HowStuffWorks.com. <http://science.howstuffworks.com/innovation/everyday-innovations/black-light.htm>  25 April 2012

http://en.wikipedia.org/wiki/Blacklight

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