Blue light when opening envelopes

[Bearworld1]

Can anyone explain this please? Yesterday I was openeing mail, the room was quite dark and as I opened each letter a weird blue light flashed from the gummed part as i ripped it open. I know this sounds very weird, I was a bit taken aback. Has this happened to anyone else?

[BillyBB]

This often happens with a particular brand of envelopes sent to me. At first I thought it was static but it could be some form of luminescence. Hopefully somebody here knows the answer.

[fo3nix]

The light is a form of chemiluminescense. Separating the two gummed surfaces requires energy that breaks the attractive forces between the gum. When you pull the envelopes apart, you provide excess energy, which lifts the gum molecules into an excited state. They like to be as low energy as possible though, so in order to lose energy, they release photons of visible light. Because of the energies involved, this determines the energy, thus frequency, thus colour, of the released photons. In your case they're blue!

[NiceCupOfTea]

Wow - what brand of envelopes? Seriously, I need to try this at home.

[Bearworld1]

Thanks a lot fo3nix, that was a great answer. As for the brand, I think it must work for most as I opened several items of mail and it happened with all of them. Thanks again for the response.

[fo3nix]

I think it's probably more common for the self-sealing envelope, due to the stuff they make them with.

[brachiopod]

Oh dear, in the not-too-distant future, I sense that Missus Pod is going to be asking me why I'm opening the mail in the dark.....

[Paddymanc]

I know a UV tracer is added to the adhesive so one can track the adhesive on the production line...this is the source of the above explanation

[Greeno]

thats quite freaky cos i saw it for the first time today and thought i was seeing things. Glad someone knows whats going on!!!!!

[greeneyes]

ive noticed it too..its weird