How cool would it be to receive an invite to an event with instructions that to magically uncover the content of the invite you need to hold it over a light bulb. And when you do, slowly, a secret message begins to appear before your eyes. Sounds a little like something out of a Sherlock Holmes novel. But it’s actually made possible by a company called J. Herbin (the oldest name in ink production in the world).
Their Invisible Ink, which retails for about $16 USD, comes in a 30mL bottle. The ink looks pink in the bottle, but it goes down clear.