The sun also emits visible light so your pupils in your eyes contract to reduce the light getting in. Pure UV doesn’t have same effect so your pupils pen up to let more light in…ooops.
We use our UV S2+ with a ZWB2 lens to find puppy urine in carpeting. My youngest son (19) is into rocks these days and has take over the flashlight to illuminate a variety of them.
Used mine to find a transmission fluid leak on our old Honda CRV. Lit the tranny fluid right up. I also use mine to check all the hotel rooms I stay in. PSA: Never use any throw pillows or comforters for anything in a hotel room.
UV light is used to disinfect, 185nm and 254nm being the optimum frequencies –though 185nm disinfects through creating ozone unlike 254nm that kills microbes directly by, I believe, denaturing its DNA. Mercury lamps have a wavelength of 253.7nm, very close to 254nm, so they work well and are integrated into UV-C air purifying systems. While the newer power LED’s have tighter frequencies in UV-B, the light emitted from older 5mm UV LEDs was not as narrow, so a 5mm UV LED that was intended to emit near UV, perhaps with frequencies peaking between 350nm-400nm, may actually also emit frequencies above and below the peak in a wide bell shaped curve. Though intended for black light purposes, if they emit frequencies down into UV-C, even with less intensity than their peak frequencies, they will also disinfect.
I have an old ARC UV flashlight. intended for checking currency or working with identifying minerals, so UV-B or near UV, that I am sure emits some UV-C because I left it on pointing at a toilet in bad shape for most of a day. Hours later, I could smell the ozone that accumulated in the bathroom, and the next day the stuff stuck to the toilet washed down with a flush, leaving bare porcelain where the beam met it.
My hope was a UV flashlight could be used to disinfect water and make it potable, but I think to make it practical (so it wouldn’t take hours and hours), it would need to be a UV-C laser, which would be pretty dangerous to eye sight and skin, as this light will blind and cause melanoma. I have seen little mercury lamps that are intended to be purposed to be placed in a cup of water for disinfecting, but I wouldn’t trust that it can disinfect within minutes… it’s going to do something, but it takes time to kill all the microbes or enough of them to prevent getting sick from drinking the water.
Occurs to me just now, UV black lights are traditionally often used in haunted houses for effect, so that’s something else you can do with them
I saw the C8 too. I was thinking about picking one but didn’t know which one to get. It would be fun and useful for some things but I didn’t feel like doing a ton of research just to find out which one should I get.
This one looks cool. I wonder if these no name flashlights are any good or complete crap.
I have a “Convoy C8 + 365nm UV LED Flashlight with Patented Glass Filter” which uses one or two 18650’s.
It is shockingly bright. I can see where painted walls weren’t properly prepared (off-white walls appear almost black, with primer showing up as whiter areas).
The UV brighteners in steam cleaner detergent is absorbed into some thread in the carpet, leaving odd, weave patterns.
Toilets look like Salvador Dalí paintings, even after cleaning. Might be the special coating on Toto toilets…
Rocks in the landscape have crazy color patterns.
Drivers licenses and money have strong reflectance info.