> CAUTION: EMITS ULTRAVIOLET RADIATION!! etc

Could that warning be an ass-coverer ? Even though it may not
strictly be necessary ? "Litigious" springs to mind

> However, I emailed ETG asking them about the danger and they
> won't be specific.  They just say "probably not a good idea to look
> at the light too long"

Well, duh, the sun or a light bulb too. But they don't give out Darwin
Awards for nothing ;-)  --- Shame on ETG for wussing out ---

> > Your artwork will be visible because the UV has been
> > transformed into visible wavelengths, but it's hard to say
> > what level of UV reflects unaltered - I'm guessing not much.

> In this case, the LEDs are shining up through large quartz crystals,
> which apparently transmit UV easily

Ah, OK. I thought you were using the UV to make the crystals fluoresce

>  the light is directly visible as violet light

So is it the colour you're after rather than the UV ? If so maybe
a white LED with a purple filter, end of problem

> here's what the interesting part of the FDA regulations on
> UV lamps say..........

What you need to do then is work out the energy of a LED as
compared to a lamp. My guess is if you diffused it as well there'd
be nothing to worry about, and you already have the inverse
square law to help as well, as someone suggested

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