Another UV Light Question / Recommendation

Ive been on the hunt for a plug in dual bad - short / long - wavelength UV light. A couple of older threads here , but looking for more current thought, user experience. Has anyone used one of these ?

https://www.transilluminators.com/p...ld-uv-lamp-1

I notice the above is 254nm/365nm, while my current battery Leuchtturn is 254/380.

Will the above 365 work as well as the 380nm? Is the difference in the wavelength relevant?

Any thoughts, tips appreciated....

You might check on E-Bay for Spectroline products. I have purchased high quality equipment for philatelic purposes. Spectroline makes mlitary grade specification equipment that is used for looking for metal flaws among other things. The long wave on my dual lamp is not as good as my stand alone device that cost $200 thirty-five years ago, but used equipment can be found from time to time.

Tks - Will do. Do you know if 365nm vs 380 for long wave makes a difference?

The standard for longwave uv with US stamps is 365nm.
Without knowing the 380nm device, I'd guess 380nm points to some kind of uv-led thing.
The problem usually is the question of how much "other light" than the wanted 254/365nm light the thingie emitts. That tends to be worse with "do everything in one device" thingies.
(I built my own 8Watt 254nm/365nm devices in the end)

My dual bulb battery lamp I now have is Leuchtturn model L81, 254/380nm.

But the link I posted is similar to what im seeing often on the net, 365nm. So I was wondering if the difference is meaningful / will or will not work for long wave length for. stamps.

The L81 uses a 375nm uv LED for the long-wave uv bit. Typically LEDs have a spread of +/-15nm so you get light in the 360 to 390nm range. This is perfectly ok for stamps. The 390nm end is close to the visible range so you might get violet/bluish tint on your pictures, depending on the tool(s) you use if you take pictures.

The build of these battery driven hand-held thingies is not really great (all come from China). The switch and bulp starter particularly so. If you plan to use the lamp at home, look for an ac driven model as the battery drain is heavy on the short wave uv lamp.

Not plug-in, but I found the one below suitable for my needs. I had been using a Leuchturm, but I found the illumination to be fairly weak, and over the years had ruined several units when the AA batteries had leaked due to non-use. So I wanted something rechargeable.

https://www.amazon.com/dp/B0CKSVYHGS




My comments:

USB-C rechargeable.
Heavier and much more robust manufacture than the Leuchturm units or their knockoffs
Brighter illumination IMO
Only downside is that the width of the beam angle is slightly narrower than the Leuchturm so note as wide a field of illumination, but that is a minor complaint IMO

Please ask the manufacturer for a datasheet of these 254nm leds before you buy.
I am aware of leds that emit light around 270nm (and around 330nm as well). They are expensive and emit very little uvc (in the mW region).
(During the height of Covid, there were masses of Chinese businesses selling fake uvc led thingies to "sanitise your bedroom").

Thanks all. Good to know and still looking for recommendations…..

Frequently easier said than done given the anonymization of platforms like ebay and Amazon, where off-platform communication is not only highly discouraged, but frequently blocked and/or disciplined outright... compounded by language barriers.

The term "datasheet" may not resonate with the person on the opposite end, so beyond the specs given in the sales listing, what specifically should we be asking for, and more importantly, be guarding against?

The term "datasheet" may not resonate with the person on the opposite end, so beyond the specs given in the sales listing, what specifically should we be asking for, and more importantly, be guarding against?
There are basically two types of user reports on Amazon:

The first ones are praising the article like it is the second coming.
The others pretty much say "almost no uvc radiation".

I usually have my doubts about product reviews like the first ones while there is no reason the others should "downvote" the article just because...

In my times, uvc leds simply didn't exist. Apparently progress hasn't stopped here but from what I gather (in a short time), uvc leds
a) get very hot when high powered
b) almost emit no uvc in low power modes. So it will not be usable for photographing purposes, if that is one idea of using the lamp.
c) tend to degrade as the technology is not matured yet.

I understand the sentiment, but my question still stands: if we do as you say and ask for, and receive, a datasheet, what should we be looking for in it as indicators whether the device should or should not be purchased?

Basically the datasheet should contain a uvc output vs wavelength diagram showing around which wavelength(s) the output is maxed. Secondly, a voltage / current diagram and a power vs current diagram. Also operating temperatures as uvc leds tend to get hot (hence it looks like the device in the picture is basically metal, not plastic).
Also zwb2 (blocks most of the 395nm light) and zwb3 (does not really block violet/blue light) filters are not cheap so I wonder if these are foils like on the usual handheld devices. My self built devices use 2mm thick optical glass).

But I guess they don't give all this information to random customers. At the moment I don't quite see the advantage of this device compared to the L81 but maybe this is the future of handhleds.

Having gone through several L81 units:

1. This one is more robust than the L81, it feels more heavier and solid in the hand and not as delicate, although that could be a pro or con depending on your preference.

2. It is more compact.

3. It has a rechargeable battery rather than relying on 4 AA batteries (which can leak) or the contacts become sporadic.

4. It is brighter in my experience than the L81.

The cost is within $20 of, or the same as, the L81 depending on where you purchase... which I consider comparable.

Dan - that one look pretty nice. 3 wavelength too... Tks