Can we test sunglasses with our UV light?

[LEDcandle]

I've always wondered if cheapie sunglasses provided real UV protection and according to some articles on the Net, they do. But not sure how much that applies to ALL cheapie sunglasses.

So anyhow, is it possible to use our UV torches as a way to test if the glasses block out the light?

From what I read, UVA wavelength is 320-400nm and UVB 290-320nm. If my UV light is within that and I shine it at a sunglass that says 100% UV protection, will it not be able to shine through?

(Sorry if this is a dumb question, I'm a non-science guy)

I tried out one of those keychain UV lights on a few sunglasses (not sure what the wavelength is) and they shined through more on some then others, but it also seems that the darker the tint of the glasses, the less light passes through, which shouldn't be the way to measure its UV coating.

A clear lens with UV coat should be able to block out the light as well?

Would like to hear some opinions on this and whether there's any DIY way of testing sunglasses UV protection without having to go to an optician.

 

[Atomic_Chicken]

Greetings!

Instead of "seeing" how much "UV" goes through with your eyes (which is in actuality just the longer wavelength violet light, not the invisible UV), try this instead. Get some UV dye, glowing-blacklight crayons, or use a security strip on currency. Shine the UV light through the eyeglasses, and see how much "glow" you get from the UV flourescing material.

Best wishes,
Bawko

 

[LEDcandle]

Great idea!! Thanks for the pointers

 

[NoFair]

Almost all cheap plastic shades stop all UV light from going through them. But shining a UV light through them at an item that normally glows under UV will tell you for sure.

This will only make you sure for that part of the UV spectrum the light is emitting though.....

 

[JNewell]

Funny you should mention this - I tried this, just as an informal experiment. I was surprised at how effective the sunglasses were.

 

[LEDcandle]

Yeah, just tested out this method... its great! And fun!
Now I can buy cheapie sunglasses without too much worry...