Review: UV light shootout, seven lights tested

Great review... and great collection of UV drop-in/flashlight and of banknotes!

Seems that TK gives the best results.

Oustanding Comparison, mfm! I know that took a lot of work to do....thanks for your effort. This once again reminds me I don't own a single UV light.... I really need to fix that

did you rob a bank or something?!? thats a lot of green :-)

I'mk curious if your TK performs the same. Can you check yours if it is in line with the above pictures? It would piss me off if variation is substantial.

You can check my results with a 20EUR bill here: https://budgetlightforum.com/t/-/1910

Looks very similar to mfm's.

Wow, I'm guessing that was a lot of work. It was quite interesting to see all of those bank notes and the different flourescent designs. Makes my national currency look boring.

Thanks everyone!

Maybe a little with the 50 SEK but probably not with the 20 EUR (except for the red stars it's hard to see any fluorescence with the violet light from the near-UV spectrum). I can take some pictures later and post them if I see any detectable difference.

BTW, does your TK-566 have a plastic lens?

The TK-566. Maybe the 365nm Ultrafire at KD can put out the same light for half the price, but we don't really know if it does and the smaller AA form factor of the TK is nice.

I don't know how to check if it is glass or plastic, but it looks glass.

I can't take the head apart for closer inspection, since it's glued to the body.

Is it glued with yours also?

Knock on it with something metallic, a knife perhaps. You cannot fail to assess the sound of glass vs plastic if properly knocked on it.

It sounds glass, but the sound is dampened by its being fixed in the flashlight's head.

Maybe there's an o-ring there?

Anyway, it sounds midway between glass and plastic.

Then a needle test. Glass sould not let the needle stuck by pushing it on the lens. Try on the edge (to avoid having some visible damage) if you're not concerned knowing you have a 0,3mm hole in the plastic lens somewhere.

First it looked like plastic because of some very small scratches, but maybe it is coated glass, I noticed that reflected light shimmers somewhat on the surface. It is specified as "Toughened ultra clear glass lens with AR coating" on the Tank007 site, but I don't trust these specifications very much. I wouldn't try with a needle...

I didn't try to open the head, but it took a lot of force to get the tailcap off the light when inserting the battery, so I would assume that the head is just tightened very hard. I don't see any glue from the inside either.

Then it's probably glass with plastic AR coating.

Thanks, mfm. That had to take a while to put all of that together, let alone the time it took for you to run around to all of those different countries. I didn't even realize the extent to which UV is being used in notes, but it was fun seeing all the different possibilities.

Comparison added to the first post.

I wonder if the T5 light is a bit underpowered, I run it with 4 x Eneloop AA but the voltage for the T5 tube should be 6V (the manual says to not use rechargables but that's usually crap). May have to find some alkalines just to try, don't have four of them at home.

Looks like the TK is better regardless of the voltage to the T5.

It's not only that the T5 is weaker, it also seems to not cause fluorescence at all in some of the places the TK does.

But maybe it really is just the input power.

I tried with four alkalines today and no noticable improvement, as expected.

But it seems to me that that the T5 causes fluorescence in all the same places as the TK? Just weaker and it's not that easy to see on the pictures (and the green part of the euro is very hard to see because of the violet light).

Even though this 4W version is a little hard to use because of the visible light, generally there is no doubt that fluorescent tubes are way superior to LEDs for generating 365nm (or lower) UV. Even if you buy a Nichia drop-in for 160 EUR it will be easily outdone by a fluorescent lamp costing much less (but the LED is easier to bring with you).

I really need to buy a fluorescent one some day.

Where did you buy yours? I remember a seller on eBay that had them but I can't find him.

There's also a comparatively cheap 254nm version: http://cgi.ebay.com/254nm-Ultraviolet-Pocket-Lamp-Shortwave-Bonus-M12_W0QQitemZ370510530344QQihZ024QQcategoryZ3226QQssPageNameZWDVWQQrdZ1QQcmdZViewItem#ht_3228wt_1139

I wonder how safe it is... and how effective it is.

I bought this one, it's even cheaper now than when I bought it: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=280590817370&ssPageName=STRK:MEWNX:IT

But you don't need it if you have the TK...

Shortwave UV is much more dangerous so I wouldn't bother with it. With high-powered shortwave UV you must have both eye and hand protection, maybe the 4W isn't that powerful but anyway. I already had enough trouble from the lights I own, briefly I looked into the 3W drop-in without thinking when I had the protection glasses on (not a great idea).

Here is how bright a banknote fluorescences under a high-powered tube light, I would guess it's a 16W or 20W tube: http://www.youtube.com/watch?v=JNKkCmXBAg8&feature=related

Looks like the TK is the only one worth bothering with. The UK mint warns that no LEDs are likely to give short enough wavelength light to check the security features

http://www.bankofengland.co.uk/banknotes/kyb_lo_res.pdf