Re: UV Sources

Judy Seigel (jseigel@panix.com)
Thu, 30 Nov 1995 03:22:24 -0500 (EST)

On Thu, 30 Nov 1995, John Rudiak wrote:
> the F40BLB's are definitely not useless for our
> purposes, they merely required twice the exposure times of the unshielded
> tubes, and you didn't need to wear UV blocker sunglasses when printing.

Who told you that you didn't need UV blocker glasses for the BLB bulbs?
That's not what I heard and I would suggest you double check. What the
so-called "shielded" bulbs shield is not harmful rays -- the UV of the BLB
is more or less the same 360 nm* as the BL. It just screens out VISIBLE
light, that is, light closer to our visible spectrum and hence less harmful
than the 360, which is itself what they call "longwave UV" and not nearly
as dangerous as all the fuss would suggest.

Until about 5 years ago, when everyone got lawsuit happy, the mfrs assured
us that UV light was "perfectly safe." We don't need to take any more
chances anywhere, but between the two I'd put my money on the BL ...Though
it isn't really very bright and so probably wouldn't cause the iris to
contract enough for utmost safety, it's brighter than the BLB and hence
would have some effect along those lines. And apparently the BLB can give
a false sense of security (though I find it pretty spooky looking....) The
advisory to date, BTW, is that harmful rays, from the medium to the short
wave UV, are screened out by glass.....not just the glass on the bulb, but
your regular eyeglasses.

The reason to wear UV blocker sunglasses outdoors is that there's no glass
between you and the sun. However, manufacturers will no longer say much of
this...if somebody got cataracts in 30 years they could be sued.

*The AQA bulbs are 415 nm, which ought to, at least theoretically, make them
"safer" than the BL. And I'll add that even today's skittish
manufacturers declare that you're safe at a distance of 40 inches from the
bulb.

Judy