Do you know your blacklight UVA from your germicidal UVC?

When buying Ultraviolet (UV) light bulbs, it’s important to know which type of light bulb is the right one for your needs.

At Lightbulbs Direct, we sell three different types of UV light bulb, and (here’s the important bit) one type is not suitable for all uses. A blacklight blue (BLB) light bulb won’t help you kill flies, just as a germicidal UV tube won’t help you detect forged bank notes. Once you’re aware of the different types of UV lamp and what they should be used for, picking one will be a lot easier.

With that in mind, here’s everything you need to know to buy UV light bulbs in confidence.




What is UV?

It is often referred to as ultraviolet ‘light,’ but UV is a type of electromagnetic radiation with wavelengths shorter than visible light and longer than X-rays.

Electromagnetic Spectrum Ultraviolet Wavelength

All electromagnetic waves are measured in metres, but some wavelengths (like UV) are so small that they’re measured in nanometres (nm). You will often see product descriptions on Lightbulbs Direct reference the ‘nm’ range of the lamp because it directly affects what type of light bulb it is.

UV radiation falls into three categories depending on its wavelength: UVA, UVB and UVC. The shorter the wavelength, the more energetic the radiation, and the more harmful it can be. Shorter wavelength radiation, however, is less able to penetrate human skin. The sun gives off the most harmful UVC rays, but they are not strong enough to penetrate the earth’s atmosphere (luckily for us).

The chart below shows the respective wavelengths (in nm) that different types of UV lamps produce, and where they fall on the UV spectrum. The three different types of UV light bulb available are Blacklight Blue (BLB), Blacklight (BL368), and Germicidal.

Ultraviolet Spectrum

These are each meant for very different uses and, in the case of germicidal lights particularly, could be hazardous to your health if mixed up. With that in mind, we’ve put together a handy guide to help you determine which UV light bulb is the right one for you.


Blacklight Blue (BLB)

These are the type of ‘glow-in-the-dark’ light bulbs that most would associate with ultraviolet light. The wavelengths that these UV lamps emit are between 370–400nm, right on the border of visible light. Typical uses include:

  • Anti-theft protection
  • Nightclub lighting
  • Detecting forged bank notes
  • Carpet cleaning (to detect stains)
  • UV nail lamps
  • Scorpion detection!

BLB light bulbs are covered by a very dark blue or purple filter, and give off a purplish glow. Fluorescent tubes – either straight or turned into more compact shapes, like the example pictured – are the most common type but there are other lamp varieties available.

When using BLB lamps with UV varnishes or paints, check the manufacturer’s guidelines on the correct lighting needed to activate their product.

While BLB light bulbs are not hazardous to your health in the same way that germicidal UVC light bulbs are, they should always be handled with care. Wear gloves when handling them to avoid contaminating the light bulb, and ensure they are disposed of safely. Avoid long exposure where possible.

See here for some more advice on the safe handling and disposal of light bulbs.


Blacklight (BL350/BL368)

Blacklight lamps are not to be confused with the blacklight blue type described above. While they still fall into the same UVA bracket on the ultraviolet spectrum, the slightly shorter wavelengths (between 350-370nm) result in very different effects. Common uses for these light bulbs include:

  • Bug zappers (the UV light attracts bugs)
  • Suntanning
  • Polymerisation

They emit a mixture of ultraviolet and visible light and will appear to glow a luminous blue colour when operating.

Again, ensure these light bulbs are handled and disposed of with care. Here’s that link again with more information about the safe handling and disposal of light bulbs.


Germicidal

These lamps have the shortest UV wavelengths (between 200-280nm) and as a result are potentially the most harmful. Accordingly, extra care should be taken when handling and using these types of UV lights.

The type of UV radiation these light bulbs emit targets the DNA of microorganisms, causing cell death or making reproduction impossible. They’re certainly not the type of light bulbs to be used in the home. They’re mainly used in professional and industrial environments in processes such as:

  • Water treatment
  • Disinfection
  • Sterilisation
  • Food sanitation

Like blacklight UVA lamps, germicidal UVC lights are commonly sold as tubes, either straight or turned into more compact shapes. Unlike the UVA lamps, germicidal tubes are usually transparent.

Wear protective clothing when handling germicidal UVC lamps and keep them away from your skin and eyes. It is best to avoid prolonged exposure to the light when it is in operation.

If you’re still in doubt about what type of UV light bulb you need, please contact us for more information.

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Vincent Lobo
Vincent Lobo
February 22, 2020 2:56 am

Where can I get these U V blind or tublights

BW LEE
BW LEE
March 14, 2020 11:28 am

Which ones are the UV-C bulbs and can you please state the wavelength?

YF Chan
YF Chan
March 2, 2020 10:35 pm

can I use uvc in fridge to ensure food stay fresh and germ free to eat ?

Joaquin Trigueros
Joaquin Trigueros
March 11, 2020 7:03 pm

Where can I find fittings for some of these tubes? I would like to build a decontamination box. Are these only for water purification systems? T8 18” wemlite, for example. Thank you.

Famous
Famous
March 12, 2020 3:49 am

Hi how do I know that something being marketed as UVC is actually a plain UV bulb? Been scouring the web – can’t find anything. Please help!!!

Charles Johnson
Charles Johnson
March 17, 2020 12:56 am

Purchased UVC LIGHT TO PLACE IN AIRVENT RETURN FOR HOME.WILLBE VISIBLE THROUGH FLOOR VENT GRATE.IS THIS DANGEROUS IF ANYONE LOOKS DOWN INTO VENT.HAVE PEYS ALSO .

Joe
Joe
March 22, 2020 11:29 pm

Are UVC tubes compatible with fittings for fluorescent tubes? Or is the starter different?

eay henderson
eay henderson
March 26, 2020 4:30 pm

will the 56t5/blb kill the corona virus? if not bub can use its;s place will?
thank you,
rhaga@att.net

Barry McLaughlin
Barry McLaughlin
April 1, 2020 10:34 pm

I have a UVC bulb and I was testing it to see if I can adapt it to perfom sterilization practices but I connect it to a power source and couldn’t see any effect. I was wearing Safety goggles from Uvex that absorb 99.9% of UVA and UVB but then I thought that because the UVC light is beyond the wavelength of the human eye I wouldn’t know if the bulb was working or not? Is there any way to rig up a sensor or any way to determine if the bulb is working? Pardon my lack of knowledge on… Read more »

Trevor
Trevor
July 21, 2020 9:22 pm

Generally the UVC lights include a secondary element within the bulb that will make the lamp appear as a blue glow when turned on (Very obvious when lit). However you are correct in that if it was only UVC light, it would be invisible.

todd
todd
April 3, 2020 11:58 am

can i use a black light bulb to clean a N95 mask

Liz
Liz
April 4, 2020 2:00 pm

I’m interested in sterilizing a room and was wondering if you had a desk top version that could be set on a timer and turned on during the night, when no-one was present.

Evangelinn
Evangelinn
April 27, 2020 3:23 am

Hello there….I am Evangelinn and I am interested in using UV-C LIGHT TO KILLS POSIBLE GERMS AROUND MY HOME….WHICH PRODUCT WILL RECOMMEND FOR ME ?

Dave
Dave
May 2, 2020 6:00 am

I was thinking of making something, using UVC LEDs. What would the range of light be, to kill any pathogens? Or how close would a pathogen be by the LED before its killed?
Do you sell the LED types?

Dave
Dave
May 5, 2020 12:43 pm

Cheers for that, I’ll take on board what you’ve said 👍

Christina
Christina
May 16, 2020 3:44 pm

Can party black lights with uv wave length 405 be used to kill Corona Virus?

Manoj joshi
Manoj joshi
May 29, 2020 1:16 pm

what is the wave length of non Fluorescent coated tube

Luke Bonner
June 9, 2020 7:00 am

Hello, I’m looking for broad wavelength UVB fluorescent replacements for a project. Do you sell these? I need 600mm and 1200mm, with two-prong pins.

Pranesh
Pranesh
July 28, 2020 11:55 am

Hi. We have installed 12 no. UVs for a fish pond. As soon as we start up, all the bulbs are flickering at random intervals. These UVs has got electronic ballasts and there is no voltage drop as well. Can someone advise the reason. Supplier said I need to replace all the ballasts and the bulbs as both might have been damaged. Before replacing would like to know the cause.