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Chmistry buffs: IR invisible ink? Answered

Hey all science-type people,


I've seen invisible ink pens and things for sale that contain ink that show up in infrared, instead of ultraviolet light.  That's really appealing to me for a number of project ideas because digital cameras pick up IR exteremely well (especially with their filter removed).

The problem is I think I'm going to want a lot of it, and those dumb little pens are crazily expensive.

So any of you chemistry buffs out there have a secret formula I could make?  I'd prefer something invisible in regular light, but hey, whatever you've got. :)


Thanks in advance for your help,
-Kurt

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I make IR ink. I also have the filters needed to see the ink. Contact me for more info

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Anyone had luck with making the IR ink?

Indocyanine Green should do it.

L

Thanks! Good lead, but from what wikipedia says it has a half-life of like 2 minutes. Rats.
http://en.wikipedia.org/wiki/Indocyanine_green
So I don't know if that'll really cut it. (Unless I'm missing something, which is entirely possible)

But that did get me hammering on wikipedia more, where I found this:
http://en.wikipedia.org/wiki/Glow_stick#Fluorophores_used

Unfortunately there are no articles for any of the IR "Fluorophores". (Plus that's also me making the assumption that they are IR-visible outside a glowstick.)

Anyone know any more info on Fluorophores? Or any tips on how to buy dihexyloxyviolanthrone from Walgreens? ;)


That's in vivo it's metabolised rapidly by the liver.

L

An ink that is invisible in normal light, but shows up under IR light?

Or an ink that is invisible until observed through an IR camera?

Do you have a link?

Link:
http://www.maxmax.com/aXRayIRInks.asp

$18.50 per pen... so um, yeah, the ink is probably like $10/oz.

Ah, an ink that is invisible until observed through an IR camera.

I understand - it fluoresces in the IR. I thought you meant it fluoresced under IR light.

Have you tried googling for infra red fluorescence?

. See if you can find out what is in the pens (might find an MSDS or similar on manufacturer's web site) and buy the material(s) in bulk.

I found this. All greek to me, but it probably says something important.
http://www.freepatentsonline.com/5684069.pdf