I have what are known as transitions glasses, they darken in response to UV light. On a bright day it seems to take about 3 minutes to darken completely.


before
Transitions start at about a 5% tint, so they aren't as clear as normal glasses.


during


Afer 5 seconds

That must mean, since I'm not a physics major, that there's 5 bajillion million billion times more UV coming out of these lamps than from the sun. Granted you have to be 6" away. I was quite curious as to how much UV these things put out. I don't have a sheet of glass to see how significantly UV transmission is reduced.

I'm not sure how bad the UV are on these things but there is the UV filter available in the shop which supposedly reduces the UV intensity. Even then, I'm always amazed at the pictures with small children staring directly into the lens for reference shots in the Project Gallery! I think that even if there was no UV output I wouldn’t want to stare into the lens without welding goggles on. I just love my eyes. But then again I could be overstating the harmful potential of LL Pjs. I haven’t built mine yet so this is just conjecture.

Wow, are these projectors safe?!

my glasses will do that if i enter a bright room.

Really? So you think the projectors are safe? I can't see why they wouldn't be, it's not like you are staring directly at the light for any length of time, plus if you have the UV filter I'm sure you'd be just fine....

If you put the UV filter half in you can see how much light it sucks up compared to the non filtered area, it also kills the colours a bit. I have watched my last few movies without the filter in. I know this might eventually bleach the LCD but more worryingly will I turn into a wrinkly old bag before my time or get cancer on my nose from the reflected light? Don’t the bulbs themselves have UV filters built in? I think I’m gonna put that filter back in.

I'd rather not take the chance without the filter, if you don't have your eyes, you can't watch anything....

Cant argue with that .

Oh No! My Da-Lite is going to get Cancer!

Seriously. You're more exposed to UV standing in a parking lot lit up with these lights than you are from watching movies from your PJ.

Given all the elements the light passes through, your likely not getting ANY harmful UV even if you stand in the prjection path.

You sure about that? I just don't wanna take any chances here....

We all should buy a bottle of SPF30 and coat the lens with it!!

********

Seriously though think about UV, and then think about Xrays too. I assume someone has looked at the spectrum output data sheet, to see if their is anything significant. Why would these bulbs be sold for aquariums, and plant growing, if they were dangerous?? People have been looking at aquarium fish for years.

Here's an idea:

Build your Pj as usual. Close the box. Turn on the LCD and the MH lamp. Take those glasses and put them in front of the PJ during normal viewing. This will give you an idea of the amount of UV leaving the projector. Then take your glasses and put them in front of the screen so that only reflected light from the screen hits them. This will give you an idea of how much UV the viewer is exposed to.

Not a hard experiment to perform. Let us know.

I believe the thing you "don't" want to do, it fire up your light in an open PJ box exposing yourself to "direct" light from it.

Doing so for short periods at a times for tweaking and such is not going to hurt you. It's "prolonged" exposure that will do the damage.

One thing to note. When you DO have your PJ open and are working on it with the light going, ALWAYS wear some kind of eye protection, i.e. UV blocking sunglasses at the minimum.

Your skin can take short exposures to the light no problem. But your eyes are much more sensitive and should be protected.

NOW, once you have the enclosure all sealed up and no "Direct" light is coming from it (I hope you can design it to accomplish this), then you are pretty much safe from UV rays.

I wouldn't go sticking my Eye up to the triplet lens though to see how Bright it is!

Of course when you "first" turn it on and the bulb is a mere glow, it's not going to hurt to take a peak inside.

Best thing is to just use common sense.

Again, the "projected" light coming from the PJ is NOT going to hurt your skin, at all... or your Eyes (unless you are directly looking down the triplet).

Go into Lowes... Look up at the ceiling. You will see many many many of these lights being used to light the place up. Bare bulbs! Not filters.
If they were "bad" for you, they wouldn't be using them.