How to invisible ink
The delight of invisible ink is timeless. It was cool when we were ten; it’s even cooler at an executive dinner when a room full of CMOs least expects it.
You might be thinking: “I don’t have any secret messages worth sharing.” You’re either overly modest or thinking too literally.
My former employer and current client, 6sense, famously coined the Dark Funnel™ to describe the digital breadcrumbs buyers leave behind while researching anonymously. What better way to make the Dark Funnel unforgettable than having your guests’ actual anonymous intent data printed in invisible ink on the menu sitting right under their nose?
Not dealing in intent data? No problem.
Got issues with shadow IT or shadow spend?
Is an invisible hand steering your market?
Do your buyers constantly complain about hidden costs?
Any of these concepts give you the perfect excuse to print the unseen.
The Ill-Advised Shortcut
A quick search will reveal dozens of cheap "invisible ink" novelty kits. Take it from someone who has tested them all (and ruined plenty of fine linen cardstock in the process): cheap shortcuts deliver dim, disappointing reveals.
If you want a reveal that actually gets a room of executives to gasp, here is the battle-tested setup.
Prep
The Invisible Ink Printer: You need a dedicated printer loaded with UV fluorescent ink. I use VersaCheck cartridges (specifically designed for HP/Epson models).
Invisible Cartridges: Ensure your cartridge matches your exact printer model before ordering.
Stealth Paper (Optional, but recommended): Standard paper works, but $30 stealth paper yields ultra-high contrast under UV light.
UV Flashlights: Don't skimp, but don't overspend either. VersaCheck sells a nice one for $10. A 4-pack of $4–$10 UV keychains or mini-flashlights off Amazon works wonders. (Pro tip: Buy extra AAA batteries!)
Technique
The process of creating your invisible ink document is straightforward.
Create one document for the visible ink and a second document with what you want revealed.
Put your stealth paper into the printer.
Print the invisible part using the printer and invisible ink.
Using one of the UV flashlights, confirm it looks the way you want.
Be sure to feed the paper in the proper direction into a printer with regular ink and print the visible document.
To execute, think about where your hidden message can be hiding in plain sight. If your event is a dinner, the fancy restaurant makes it easy to conceal. Print your hidden messages on the printed menu that is common for a multi-course meal. Sure, some guests may pick up the menu to quickly read what’s on the menu for the night, but they’re not studying it, and many won’t touch it all. For your event, think about a place where a piece of paper would be common but innocuous. That’s your hiding place.
Hand out the UV flashlights with a helper just before it’s time to use it. If you place it somewhere guests can grab it before things start, you run the risk that a guest gets curious, turns it on, accidentally points it at the menu, and the surprise could be spoiled.
Dim the lights (the room doesn’t have to be pitch black to work, but the darker the room, the better)
Ask your guests to turn on their UV flashlight and point it at their document, and Voilà! a message your guests will never guess is there.
Coup de grâce
Can guests keep the flashlights as souvenirs? Absolutely.
While most people don't have much use for a UV flashlight at home—short of detecting pet stains—gifting the light ensures your brand stays top-of-mind long after the final course. And for any lights left behind? Pack them up for your next dinner.
