Blue/Violet + glow in the dark ceiling safety.

[7h0m]

Recently I saw some glow in the dark paint at Home Depot. Knowing that a Blue/Violet laser would make it flouresce and glow I bought enough to paint the ceiling in my living room and grabbed a couple of pointers off Amazon. I know they aren't the cheapest for a low quality pointer but Amazon returns are easy and the shipping was free and fast.
This is the pointer in question:
Amazon.com: 10mW Blue Violet Laser Presentation Pointer: Office Products
It says 10mW, but the label says it is class 3A. The beam isn't visible, has high divergence and the quality of the spot is terrible. Though I just want it to draw on the GITD ceiling, which it does very well, so no worries.
My question is this, after drawing on the ceiling for a while last night I am feeling a lot of eye strain (soreness around the eyes); no spotting or visual problems.
I wasn't wearing goggles, and for this project I want to keep it within 3A limits so that they aren't really needed. Could you guys comment on the safety of using a <10mW blue/violet on fluorescing materials at a range of 2-3m?
The surface is matte and there is a low probability of specular reflection.

 

[KiLLrB]

I dont think you have much to worry about but safety goggles are always reccomended with 5mW or greater lasers.

 

[AndyR]

I believe the eye strain is because your eyes are attempting to 'focus in' on the dot, but at this wavelength it is very difficult. That, or it could be the fluorescence that is hitting your eyes, but should be safe because it is not collimated nor coherent. Either way, I think it shouldn't do any harm to your eyes but I still wouldn't stare at it too long if it is causing soreness.

 

[ninja_tux]

^ I would definitely agree with this, our retinas aren't adept at sensing 405nm light, so the image is blurry. Our brains don't like this and tell the eyes to focus and "clear up" the image, causing your irises to dilate and contract, which, like any other muscle, makes them sore.

And as long as you don't get a reflection hit you should be ok.

Btw, cheap violet pointers are notorious for being grossly overspec, for example my "10mW" from O-like really puts out about 18mW.

 

[7h0m]

Thanks for the help everybody, it is much appreciated!
Is there any easy way to get a decent ballpark idea of the actual power output of these pointers? If it really is >= 10mW I don't think this may be a good idea as I can see this getting played with frequently which increases the chance of a simple mistake hurting someone.

 

[ninja_tux]

Thanks for the help everybody, it is much appreciated!
Is there any easy way to get a decent ballpark idea of the actual power output of these pointers? If it really is >= 10mW I don't think this may be a good idea as I can see this getting played with frequently which increases the chance of a simple mistake hurting someone.

Unfortunately if it's less than 50mW there's no great way to tell without an LPM or a laser of known power to compare it to. You could send it to a member with an LPM if you really do want to know, or if someone lives close enough you could probably drive and have them compare it. If you're interested, just ask around, most people on this forum are more than happy to assist their fellow laser hobbyists

 

[AndyR]

The only way I could think of (without using an lpm ofc) is checking to see if it can pop a dark colored balloon / make tiny marks in black plastic. If it can it is probably at least 30 mW, but then again this is a very rough estimate due to many factors that can affect burning ability like dot size etc.

Chances are it won't be able to burn anything, then
personally I would just use the laser carefully and avoid pointing it anywhere near people / reflective objects (and don't let your friends use it either, unless you are sure about their knowledge about laser safety) rather than stop using it altogether.

 

[Bluefan]

If a laser can burn, it's really dangerous. If you focus it and it can burn, it's still very dangerous. I can't decide for you, but I'd still consider it class 3B unless determined otherwise, which means goggles on.

 

[7h0m]

Yeah, I think I'm gonna just play it safe until I actually have Blu-Violet hardware with confirmed output.

 

[derangboy]

I purchased a couple of cheap blue/violet pointers off eBay advertised as <10mw. On the LaserBee they both put out just over 30mw. Just something to keep in mind for your eye safety. I use UVEX SCT Orange safety glasses with my BluRay (about $8 at the local auto store). On a direct hit, mine pass 4% of 405nm over 30 seconds at 60mw.
Do you have pics of your GITD handywork? I think it's time to repaint my hobby room....

 

[MikeBP]

If you are using them at night ALWAYS wear glasses, your eye cracks open at night so iirc you are actually more susceptible to damage when in the dark.

and 50$ oh my lord I got my pot modded 5mw (was 5mw then pot modded) for 13$ shipped and im pretty sure its the same cheapy laser pointer.

 

[Uranium]

I think you should post pics!

 

[DiRollin]

YES! thats such a cool idea!!