# Questions about UV lights



## Sarge120867 (Oct 30, 2019)

I work in the pest control industry. I am looking to pick up a good UV light to use for inspections for rodents and bed bugs. I am looking at the Nitecore MT1U at the moment but was wondering if there are better options available?


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## Rasher (Oct 30, 2019)

Engenious Designs FyrFly - superior output, comes with visible blocking filter for better contrast, same price zipcode...


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## CobraMan (Oct 30, 2019)

Check out the EagTac P200LC2 UV - I picked one up recently and it is an excellent light powered by an 18650 cell and with 3 levels of brightness. I am very happy with it and would buy it again for whatever that is worth.

Cheers,
Tim


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## PhotonWrangler (Oct 30, 2019)

The magic term is *365nm* wavelength. This is the classic "black light" wavelength. The less expensive 395-405nm near-UV lights put out a lot of visible purple and thus don't fluoresce things as well.


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## Sarge120867 (Oct 30, 2019)

PhotonWrangler said:


> The magic term is *365nm* wavelength. This is the classic "black light" wavelength. The less expensive 395-405nm near-UV lights put out a lot of visible purple and thus don't fluoresce things as well.


I have read this in doing my research. 
Thank you.


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## Sarge120867 (Oct 30, 2019)

CobraMan said:


> Check out the EagTac P200LC2 UV - I picked one up recently and it is an excellent light powered by an 18650 cell and with 3 levels of brightness. I am very happy with it and would buy it again for whatever that is worth.
> 
> Cheers,
> Tim


This looks like a good option.


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## lightfooted (Nov 1, 2019)

My Nitecore P20UV works well and is according to the packaging a 365nm UV light. It also has an XM-L2 for white light. Only downside is that is has a battery spring on only one end, the head side has no spring at all.


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## syga (Nov 3, 2019)

I don't know about rodents, but I use a uv light for finding leaks in automotive fluids with dye.

There was another thread here that recommended this light with the 365 Nichia led, I bought it.

https://www.gearbest.com/led-flashlights/pp_277704.html

I haven't tried all uv lights, but this is the best I've ever used. Just use some clear uv blocking goggles with it. Note that it does not include a battery.


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## Dave_H (Mar 15, 2020)

PhotonWrangler said:


> The magic term is *365nm* wavelength. This is the classic "black light" wavelength. The less expensive 395-405nm near-UV lights put out a lot of visible purple and thus don't fluoresce things as well.



 At the low end, at Home Depot I recently got a 3AAA UV flashlight for $6; uses multiple cheap 5mm LEDs and shows a fair
bit of visible, but good to play around with. Also nice that it can take an 18650.

I don't have specific use, but notice they are good for detecting scorpions! I will check under my bed right away!

_4.5h / 1m drop resistance 9 LEDs Great for Leak Detection, Reading Fluorescent Inks, Detection, *Scorpion Detection* 
(3) AAA BATTERIES INCLUDED. UV Light_.

Going way back, my first UV light was a modest cost lab-use device using mercury tube and filter. Two versions were
offered, 3660A (366nm, "long wave") and 2537A (253.7nm, "short wave"); I got the latter. Original use was finding
fluorescent minerals; later to erase UV EPROMs. I had fun making day-glow posters and powdered detergent
(with optical brighteners) light up in the dark. It still works.


Dave


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## PhotonWrangler (Mar 15, 2020)

Dave_H said:


> Going way back, my first UV light was a modest cost lab-use device using mercury tube and filter. Two versions were
> offered, 3660A (366nm, "long wave") and 2537A (253.7nm, "short wave"); I got the latter. Original use was finding
> fluorescent minerals; later to erase UV EPROMs. I had fun making day-glow posters and powdered detergent
> (with optical brighteners) light up in the dark. It still works.
> ...



Your experience matches mine almost exactly, I also used SW for finding fluorescent minerals and erasing eproms. I even discovered some phosphorescent rocks in our own driveway. They glowed a pale bluish-green after I turned the light off. That was the coolest thing.

And today those shortwave lamps can double as germicidal devices, especially with the filter removed.


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## Dave_H (Mar 17, 2020)

PhotonWrangler said:


> The magic term is *365nm* wavelength. This is the classic "black light" wavelength. The less expensive 395-405nm near-UV lights put out a lot of visible purple and thus don't fluoresce things as well.



Old tube lamp is Ultra-violet Products UVS-11. Verified it works and have a spare tube from an air purifier.

In a Canadian Tire store I saw a set of UV LED "inspection lamps" which are just over-sized penlights; one 365nm, other 395nm. Don't recall the brand/price, will try to get more info next visit. Can't seem to find it online and some of their webpages hang my browser for some silly reason.


Dave


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## PhotonWrangler (Mar 17, 2020)

Dave_H said:


> In a Canadian Tire store I saw a set of UV LED "inspection lamps" which are just over-sized penlights; one 365nm, other 395nm. Don't recall the brand/price, will try to get more info next visit. Can't seem to find it online and some of their webpages hang my browser for some silly reason.
> 
> 
> Dave



Interesting. I have yet to see a true 365nm LED flashlight in a regular retail store. Was the "inspection" lamp intended for detecting A/C leaks or something else?


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## Dave_H (Mar 27, 2020)

PhotonWrangler said:


> Interesting. I have yet to see a true 365nm LED flashlight in a regular retail store. Was the "inspection" lamp intended for detecting A/C leaks or something else?



The 365nm/395nm inspection light pair is made by/for an outfit called "Police Security". Not bad at CDN$25 but I didn't bite. At least one of the two is offered separately.

Package mentions currency checking and leaks for 365nm; blood/urine/scorpions (!) for 395nm.

Dave


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## Dave_H (Mar 29, 2020)

Checking the cheap Home Depot "Defiant" flashlight specs, no wavelength is spec'ed. Package
shows a glowing scorpion which is leading me to think it is 395nm.(**)

Found Coast UV 1AA flashlight PX100 which actually specs 400nm.

Side note, I watch a fair number of "who-dunnit" detective series main from England, Scotland, Ireland,
Australia, New Zealand etc. In Murdock Mysteries (Canada) Det. Murdock employs a crude (at the
time, early 1900's) UV lamp for detecting blood; in a wooden box, portable.

Dave

** hmmmm...shouldn't scorpions get compensation for their role in selling these products...they're not even on the payroll!


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## PhotonWrangler (Mar 29, 2020)

Dave_H said:


> Side note, I watch a fair number of "who-dunnit" detective series main from England, Scotland, Ireland,
> Australia, New Zealand etc. In Murdock Mysteries (Canada) Det. Murdock employs a crude (at the
> time, early 1900's) UV lamp for detecting blood; in a wooden box, portable.
> 
> Dave



I'm guessing it was an incandescent lamp with a woods glass filter. G-E used to make a 250 watt incandescent with the glass envelope made out of Woods Glass. It was a brute force way of getting some usable UV, but it ran so hot that it could only be used intermittently per the specs.


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## Dave_H (Dec 25, 2020)

Dave_H said:


> The 365nm/395nm inspection light pair is made by/for an outfit called "Police Security". Not bad at CDN$25 but I didn't bite. At least one of the two is offered separately.
> 
> Package mentions currency checking and leaks for 365nm; blood/urine/scorpions (!) for 395nm.
> 
> Dave




I saw this set of UV inspection-style flashlights, one 365nm and one 395nm on sale for $20 so decided
to try.

First 365nm light failed after unscrewing the cap to check batteries (no longer lit). I detemined that
the LED head was bad. Second set did similar thing, though the 395nm light seemed OK. Seems to
be a design and/or manufacturing defect at play. Both sets returned, disappointed. Other products
under this brand are not necessarily bad.

Dave


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## PhotonWrangler (Dec 25, 2020)

I've got to wonder whether there was any current regulation on those 365nm LEDs. Hopefully they don't just rely on a series resistor.


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## adamlau (Dec 26, 2020)

395 has its place as certain fluids flouresce under 395 that would otherwise remain (mostly) unseen at 365. 395 is what I prefer when I want to check our bathrooms


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## Dave_H (Dec 30, 2020)

PhotonWrangler said:


> I've got to wonder whether there was any current regulation on those 365nm LEDs. Hopefully they don't just rely on a series resistor.




UV LEDs of this type seem to have forward voltage >3v so must be some sort of voltage boost in there, as the
lights runs from 2xAAA.

Dave


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## PhotonWrangler (Dec 31, 2020)

Ahh, thanks Dave. You are correct!


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