Buying a black light - how to pick a safe one?
March 15, 2024 6:27 AM Subscribe
I'm looking to buy a small UV flashlight to observe fluorescence in some mineral samples, but after hearing about the party where the NFT bros suffered eye damage from the wrong type of UV lights, I'm concerned about just picking a random one off Amazon. What should I be looking for, and is there a reputable supplier out there? (Difficulty: must ship to EU, would prefer to spend <€20.)
Also, sounds like disc golf suppliers might be a good, non-Amazon place to look; I also found this conversation with the same question on iNaturalist - the poster is also in the EU.
posted by sagc at 6:43 AM on March 15 [2 favorites]
posted by sagc at 6:43 AM on March 15 [2 favorites]
the NFT event used high-power lamps and people were staring pretty much right at them for a long time.
The NFT event used germicidal UV lamps, it wasn't a matter of power so much as being the wrong frequency of light, they can be dangerous, even handheld ones.
posted by BungaDunga at 6:55 AM on March 15 [2 favorites]
The NFT event used germicidal UV lamps, it wasn't a matter of power so much as being the wrong frequency of light, they can be dangerous, even handheld ones.
posted by BungaDunga at 6:55 AM on March 15 [2 favorites]
There are a number of handheld illuminators that include a laser, a white LED and a near UV LED for investigating possible urine stains -- these are marketed in the cat toy / pet departments. They are not very bright but are small and often rechargeable.
In any case, look at the specifications for the UV emitter you're considering -- you want 365nm for best fluorescence, in the generally regarded as safe UV-A range. Reference.
Stay away from anything with a shorter wavelength than 355, anything rated for germicidal or sterilization or claiming to be UV-B or UV-C.
posted by seanmpuckett at 6:57 AM on March 15 [4 favorites]
In any case, look at the specifications for the UV emitter you're considering -- you want 365nm for best fluorescence, in the generally regarded as safe UV-A range. Reference.
Stay away from anything with a shorter wavelength than 355, anything rated for germicidal or sterilization or claiming to be UV-B or UV-C.
posted by seanmpuckett at 6:57 AM on March 15 [4 favorites]
you want 365nm for best fluorescence
Some minerals fluoresce differently at different wavelengths, or only fluoresce at higher or lower wavelengths. Depending on what you're viewing, you may need both. Rockhound friend suggests having one that is 390-410nm for best results, but some minerals fluoresce even at 360nm, and he packs one of both.
Are you looking for something handheld or something for display?
UV lights are tools not toys; if you treat them as such, you'll likely be fine. You are unlikely to damage your eyes if you are viewing the light bouncing off of a mineral. Don't look directly into the lamp.
This appears to be an EU source that has a good breakdown, and purchase options. Ali-express also has a bananas amount of options, at different nm ranges, well below your desired price point (always a gamble regarding quality though).
This is a good question for a specialty lapidary oriented shop, or local lapidary club (they'll likely have good options for you locally).
posted by furnace.heart at 9:30 AM on March 15 [1 favorite]
Some minerals fluoresce differently at different wavelengths, or only fluoresce at higher or lower wavelengths. Depending on what you're viewing, you may need both. Rockhound friend suggests having one that is 390-410nm for best results, but some minerals fluoresce even at 360nm, and he packs one of both.
Are you looking for something handheld or something for display?
UV lights are tools not toys; if you treat them as such, you'll likely be fine. You are unlikely to damage your eyes if you are viewing the light bouncing off of a mineral. Don't look directly into the lamp.
This appears to be an EU source that has a good breakdown, and purchase options. Ali-express also has a bananas amount of options, at different nm ranges, well below your desired price point (always a gamble regarding quality though).
This is a good question for a specialty lapidary oriented shop, or local lapidary club (they'll likely have good options for you locally).
posted by furnace.heart at 9:30 AM on March 15 [1 favorite]
In addition to what others are saying, you might want to consider using a pair of UV-blocking safety glasses or putting a UV-blocking plexiglass sheet in between you and the light.
posted by mskyle at 9:47 AM on March 15
posted by mskyle at 9:47 AM on March 15
Best answer: Minerals fluoresce at both “long wave” and “short wave” frequencies. The frequency used for long wave is similar to black light. This is not harmful in a significant way (as with anything, if it hurts, don’t do it! Don’t shine bright lights into your eyes. Don’t stare at lightbulbs. Regardless of the frequency of the light.) Longwave lights are very affordable. This will be fine if you’re just having fun making things fluoresce, this one is great.
Shortwave is harmful if you look directly at the light or shine the light on your skin. This is the wavelength range that causes sunburns. Shortwave lights are more expensive.
In general, put the rock on the table, point the light at the rock, and look at the rock, not the light. Longwave will probably satisfy all your fluorescent needs! But if you want to experiment with both, I’m told this light is the new hotness in handhelds- both long and shortwave in one unit! People have been trying to make something like this affordable for a long time and sounds like this one actually works ok. I haven’t tried this one yet, but I have one on the way.
My advice for setting up a permanent display would be different and would involve protective plastic.
Source: I work at a mineral museum with a significant fluorescent gallery, and earlier this week I started working to design a fluorescent tour of the other galleries based around handheld lights.
posted by Secretariat at 10:50 AM on March 15 [13 favorites]
Shortwave is harmful if you look directly at the light or shine the light on your skin. This is the wavelength range that causes sunburns. Shortwave lights are more expensive.
In general, put the rock on the table, point the light at the rock, and look at the rock, not the light. Longwave will probably satisfy all your fluorescent needs! But if you want to experiment with both, I’m told this light is the new hotness in handhelds- both long and shortwave in one unit! People have been trying to make something like this affordable for a long time and sounds like this one actually works ok. I haven’t tried this one yet, but I have one on the way.
My advice for setting up a permanent display would be different and would involve protective plastic.
Source: I work at a mineral museum with a significant fluorescent gallery, and earlier this week I started working to design a fluorescent tour of the other galleries based around handheld lights.
posted by Secretariat at 10:50 AM on March 15 [13 favorites]
Here’s a great video explaining what happened with the NFT bros.
posted by Secretariat at 11:11 AM on March 15
posted by Secretariat at 11:11 AM on March 15
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posted by sagc at 6:39 AM on March 15 [1 favorite]