The History of Invisible Ink

As a kid I had a minor obsession with invisible ink after learning about it in a science club. An impressive stack of vinegar and lemon scented papers filled my desk, but the history of invisible ink is much more interesting than a summer enrichment program. Starting with the Roman general Pliny the Elder using milk from the thithymallus plant, to modern inks which are only visible under UV light, the science of invisible ink has grown quite complex. Some of the oldest CIA documents contain recipes for special inks, and MI6 and their very own "adult" mixture during WW1.

Comments

Re:Mansfield Cumming

[_0xd0ad]

Oh, it gets better... next two paragraphs:

However, the discovery also led to some further problems, with the agent who had identified the novel use having to be moved from his department after becoming the butt of jokes.

In addition, at least one agent had to be reminded to use only fresh supplies of the 'ink' when correspondents began noticing an unusual smell.

Re:jizz not the best

[cyberchondriac]

If they had the DNA technology they have today, it could also have functioned as a chemical signature for authentication: "Yep, we tested it, the message is from Agent XYZ alright".

But then,I don't think I'd want my DNA in the hands of the enemy, should security be compromised.