You have a point.
On the other hand, and not meant to offend you: a light that emits more visible light than UV light is pretty useless IMHO. Read the reviews on this site, or on the site https://www.naturesrainbows.com/ . The Convoy I got came with a ZWB2 (black) filter, but you can buy them separately. It is a world of difference. This filter blocks the visible light, so we don’t have to ask ourselfs constantly, was that fluorescence or wasn’t it.
Nope, my UV zoomies have a glass lens swapped in.
Polycarbonate is hopelsss at 365nm (Carclo)
PMMA works, but blocks quite some 365nm light too (Ledil)
The OP describes a led that sounds like 365nm, or close, so perhaps a PMMA TIR is used.
i can;t see the UV, so how would i know what the ratio is?
i do know the light gets warmish in a minute or so, so i assume there is a lot power going somewhere, i hope it;s to the UV, not just the visible part, or the heat itself…
Most 365nm leds emit some white/yellowish/greenish light, that is apparently inherent to the design principle of these leds (385nm and 400nm leds do not have this). Nichia 365nm leds are better in that aspect, the amount of visible light they emit is minimal (but not absent). Compared to the invisible UV-light, the visible light is only a small part of the output, but it can blur any fluorescence that you want to see.
To get an idea of the ratio, point the light at a piece of white photocopier paper, the blue fluorescence (that is a measure of the UV that it comes from) hugely over-shines the visible light from the led itself.
so - given that this thing puts out a lot of bluish light, would it make sense to get a small piece of woods glass and add it to the front to filter that out?
I have the S2+ with Nichia LED. Pretty powerful. compared to my other UV lights (Kaidomain WF-501B with cheap UV drop-in + Convoy S2 bought few years ago).
Also, you can buy something like this for blocking visible light: 365nm UV-Taschenlampe Sichtbare Filterlinse 1 Stücke Sale - Banggood Deutschland sold out-arrival notice-arrival notice. Along with 18350 tube it will be pretty short light and still giving loads of UV…
Acrylic lens give a little fluorescence in UV, so may add some of the visible light as well.
Edit: sorry, didnt realize that editing can bump the post
I decided to get one of this during a promo flash sale in AliExpress.
It does emit a lot of visible white light (seems to overpower the UV light).
But if I place a ZWB2 filter (I only have a 20mm ZWB2 filter which is too big to fit inside this flashlight, so I only held the filter in front of the Nicron B10-UV), after that, the visible white light is now mostly filtered out, and what remains does look like 365nm wavelength UV (when compared to my Convoy S2+ UV365).
I’ll try to take some pics sometime for comparison…
yes that is what i did too, glue a ZWB2 filter and that fixes it.
what the visible light does is, it overpowers not the UV light, but the light that your test material might make
unless it makes a bright blue glow, like white paper or a tshirt does, you can;t see it in the whitish light from the nicron
anything faintly glowing is hard to see
For what it is worth, I contacted Nicron about their B-75 light. It showed up in one of the coupon offers on BLF but doesn’t look like it is showing up on their web page yet. It is a rotating head light with both white light and UV emitters. The description said 365nm in one place but 395nm in another. When I asked about this they said the 365nm was a mistake and the emitter is 395nm. I am guessing that the inexpensive twisty has 395nm too. If so it will limit the usefulness for UV.