Do you know your ultraviolet blacklight UVA from your germicidal UVC?

When buying Ultraviolet 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 Ultraviolet (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

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.

Types of UV light

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 ultra violet 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 our guide 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 black light 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 ultra violet 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.


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.

Ultraviolet UVC Sterilization Box

Ledvance LED Battery Sterilization Box 5W UV-C

For peace of mind we have introduced a new product to our range, the Ledvance LED UVC Sterilization Box.

Supplying reliable, simple and easy sterilisation thanks to the newest LED UVC technology.

UVC light helps destroy the DNA structure of viruses, bacteria and other pathogens, helping to stop them from spreading.

The sterilization box makes use of the sterilizing properties of UVC light with a wavelength between 200 and 280 nanometers without the need for any chemistry or any poisonous compounds.

This sterilization container is best for the disinfection of objects including smartphones, glasses, pens or face masks, leaving you and your own home protected from the threat of contamination.

Simply insert an item inside the box and close it then set the sterilization time: 6 minutes for smooth surfaces such as of mobile phones or glasses,9 minutes for porous surfaces such as face masks.

That’s it.

Check out Ledvance’s own video to see the sterilization box in operation below.

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

4.6 11 votes
Article Rating
Notify of
Oldest Most Voted
Inline Feedbacks
View all comments
Larry M

Hello, looking for a uv light or bulb that will darken spruce wood on a guitar top.

Kaaa Jay

The ONLY difference between a flourescent lamp in your house and one for disinfecting a water tank or water line is that white flourescent powder on the inside of regular tubes isn’t there. So we the consumer pay 5 to 10 times for leaving it out.


What is the best UV light to take to the thrift store to find items that glow?


Which UV bulb can I use to inhibit or kill fungal growth on a camera lens. The lens is 15cm X 6cm and thus mightn’t be suitable for one of your germicidal light boxes. I’d prefer not to have to dismantle it, but if needs must, I will.

David Ellenstein

Which is the best uv bulb for use in the furnace system? The current one is 18 watt and 9 inches long.


Please, what’s the difference between a germicidal UVC bulb with ozone and the one without ozone?

Mercy C

Please does a 15W, 254nm germicidal E26 UVC bulb have the same penetrating effect as a T8 germicidal UVC bulb of the same specifications?


What is the best UV lamp for curing liquid acrylic? I need something powerful that will penetrate through the layers of translucent hardened plastic (as it cures), and as quickly as possible. Thanks

Colin Fitch

Do you sell 100w e27 screw in bulbs, black light blue??
Thank you.


What’s the best type to detect mold and pet stains?


Hi I want a UVA bulb to help my indoor houseplants grow. Will one of your bulbs work for this please and if so which one?


Hi, I need to purchase a UVA-340 lamp could you please direct me to where to find this

Jagad eswar

Hi, where do we get a 6KW light source with UVA/UVB for application in Drug Toxicity investigations on rats and mice please?

Tina Lloyd

Are any of the bulbs ok for a parrot/bird room ?


If i want to build UV weathering test chamber, which uv light type should i used?

ian thomas

What uv lights would i need to illuminate the mineral willemite, (fluorescent rocks) i have the bLb lamps @17 watt and they dont bring all the color out?

William Allen

Do you sell any uv light for hvac system? And if so would 2 up be suitable for say a 4 ton heat pump? Thanks

Michael J Martin

I have read that the UVC bulb light was safe to :see” as long as the bulb itself was not visible. The article said that the C wavelength does not bounce, it absorbs into the the surface it hits. Any idea if this was correct? Mike 

Andrew LB

Aluminum will reflect UV ranging from 250nm to 400nm. Almost everything else will not.

Young Cho

What is the right one for uvb?

US. Silica

I need a UVA 340 tube and the corresponding fixture for testing and it has to be less than 30 inches in length


I have purchased 25 watt uv bulb to replace a 15 watt bulb of the same size in my TMC 400. the dimensions are the same as the TMC 600. is it safe to fit


They bulbs are the same dimension just 15 watt or 25 watt

Jo-Anne Frazier

If I have a gel nails curing unit (365nm) I use for curing UV resin. I need to have bulbs emitting 368nm for photopolymerization, can I get bulbs that fit the same unit? I am in the US. Do you ship?


Is ther a national or international standard for a CFL UVC bulb?

Md Sohel Rana

Do you have any light emits only UVB radiation? I am intended to use with supplementation of UVB light for layer production.

Phil davirs

Can I use uv lamps to control mold infestation

mike ross

I need to activate a bleaching process that we have traditionally used the sun to complete. What is the best type of light? Thank you!

Tracy Shea

I bought hair lightener spray. It’s activated by sunlight. We don’t have much sunlight these days. What type of bulb would duplicate the sun exposure to have the lightener develop?

bill buckley

which would work best on photosensitive PCBs


I was wondering if any of your products generate UV light centered around 340 nm wavelenght?

Peggy Biekowski

What kind of bulb would be used for psorasis?


Does the length of a uvc bulb matter if they are the same power?

Emma Wilson

Can I grow a plant using a UV light?

Gary Renschler

No. The plant will be spindly and suffer from the effects of that wavelength.

Omar Mazano

is UVC light bulb is good for sanitation and to kill for corona Viruses and any other harmful microbe element? what is the precaution before we use UVC light, because UVC germicidal lamp is already sold in the market


Can I use those lamps in sneaker cleaning? If yes, then which one?
It would be used as a sole whitening method with cleaning product Sole restorer Tarrago.


What uv light to cure liquid acrylic?


Did you find the answer to this? I am also looking


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.

Luke Bonner

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.

Manoj joshi

what is the wave length of non Fluorescent coated tube


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


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?


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




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.


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

Barry McLaughlin

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 this topic. Thanks in advance.


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.

eay henderson

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


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

Charles Johnson



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!!!

Jenny Everywhere

You can get a test card on Amazon. It should supply these functions: Show that the light is nominally in the ultraviolet range, and isn’t just a colored light, specifically show when the light is in the UV-C range, and should have a scale to show the light’s intensity. They aren’t expensive, and they last forever. I carry mine in my wallet.

Joaquin Trigueros

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.