The Tank007 TK-566 365nm is the winner of showing UV marks on banknotes. However, it is very weak, and its beam cannot cover an entire banknote. It has almost no visible light.
The Taiwan 380nm has a very strong beam, but fails to show most UV marks on banknotes. I really doubt it is 380nm - it should have at least some power in the 370nm wavelength, but doesn't look like it has it from the test shots. Maybe 380nm is the shortest wavelength it emits. Center wavelength at the 390s? Can be used as a blacklight. Has a lot of visible purple light. Has a very interesting effect - the UV marks seem floating in the air, a 3D effect! Pity I couldn't reproduce it with my camera.
All the keychain lights perform similarly: They are fairly weak and don't show almost any UV mark on banknotes. Lots of visible purple light. I could hardly differentiate them, so the 365/390/395 designation is almost arbitrary (they came unmarked from the seller), but two seem to perform identically while the third ("365nm") performs slightly better, but not even close to the TK-566 365nm. The differences could not be captured well with the camera. They're probably all in the range of 390-400nm.
The TK-566 365nm and the Taiwan 380nm probably use LEDs from the same manufacturer, as shown here: https://budgetlightforum.com/t/-/1633 . The TK-566 is advertised (in Tank007 site) as having a Nichia LED, but neither Manafont nor Tank007 could tell me the exact LED model, and it doesn't look like any Nichia UV I've seen. Still waiting for an answer from Nichia about it, though I doubt they'll reply.
I'll maybe try the TK-566 with an extension tube, although Tank007 said it should not be used with 2xAA, only 1xAA. But it won't kill the LED, right?...
I tested them with some bills I had: 50 euro, 100,200,1000 Norwegian kroner, 200 Israeli shekels.
Definitely the TK-566, but it's way too weak to be really useful if you don't know where to look. It has a useful range of maybe 50cm. Most of the time much less, especially if the substance in question isn't very fluorescent.
Wow, that was awesome. Thank you! I'm glad I've held off on buying a UV light. Those 'Tanks' are expensive, though! Considering UV is (ttbomk) the native output of LED's, it's hard to believe that making a good one would seem so tough, or quality items so scarce.
If someone can find a true "budget" UV light with similar performance, I'm in! Until then... $30+... if one doesn't have immediate use for it (although many do), might be better spent on other toys. Which does not detract from the awesomeness of this review.
I have the emitter from KD and some 365nm 5mm leds , this last very weak but I was able to discover with it some red stuff otherwise invisible in the 50 $ bill of my currency , the others bills have usual blueish stuff..
I ordered the 365nm 17 $ from KD , shipped today...
arenat, I would love to hear how the KD light performs... if it really is a 365nm (and it may well be according to the lumen rating) then it's probably the holy grail of cheap UV lights.
I'm thinking swap the host puting the emitter in a cheap or not 1AA's body with a boost circuit and using the P60 setup and body with one of the XP-G R5 I have from the XM-L's mod rush plenty of both, emitters and drivers easily modable to any current in that low range.
Do you see all of the UV features of the 50 euro bill with the TK-566? The parts that are bright yellow or bright green (on the picture from the bank) seem very faint in your picture?
plenty of both, emitters and drivers easily modable to any current in that low range.