After swapping the UV emitter in my S2+ with a higher-powered one, I noticed that the ZWB2 filter gets untouchably hot in seconds, which made me suspect that it absorbs a substantial amount of 365nm UV, not just visible light.
I ran a crude fluorescence-based comparison with and without a filter, and arrived at the conclusion that the 2mm-thick filter has a transmission efficiency of only 60%, i.e., it loses almost half of the UV going in.
This conclusion is further supported by 2 sources:
- Test of 1mm ZWB2 filter indicating around 78% transmission efficiency at 365nm. For a 2mm filter, the transmission is thus (78%)^(2/1) = 61%.
- First review under this 1.5mm filter listing includes a test result that shows 68% transmission. For 2mm, the transmission would thus be (68%)^(2/1.5) = 60%.
So, using a 2mm ZWB2 filter cuts the UV output almost by half. While this tradeoff is justifiable for mineral detection and such, it feels very wasteful, and unwelcome for applications such as resin curing or charging glow items.
Does anyone have a solution that allows visible light to be cut without such high losses? I think a ZWB2 filter with a lower pigment concentration would be ideal, but I don’t know if anyone makes such a thing.