How to invisible ink

The surprise and delight of invisible ink is timeless. It was cool when we were kids, it’s still cool today. I’d argue it’s especially cool at an executive dinner at a fancy restaurant when guests are least expecting it.

You may be thinking: “I don’t have any secret messages worth sharing.” You may be right, or you may be thinking too literally. My former employer/current client, 6sense, has trademarked the phrase “Dark Funnel™” to represent the breadcrumbs that prospective buyers leave behind as they do anonymous research on the web when evaluating vendor solutions. What better way to make the Dark Funnel™ unforgettable than to have the guests’ Dark Funnel printed in invisible ink on the menu that’s been sitting under their nose the whole time.

Maybe you could hide something about “shadow IT” or “shadow spend”? Does an “invisible hand” play any part in your business, or “invisible assets”? Are the phrases “hidden agenda,” “hidden costs,” or “hidden gem” frequently used in your discipline? Any of those phrases can be the perfect excuse to employ invisible ink.

The Ill-Advised Shortcut

There are lots of products purporting to be invisible ink, almost all cheaper than the solution I’ll outline below. In my firsthand experience, all of them deliver less-than-stellar results which is why I believe so strongly in the solution I finally came upon.

Prep 

For this exercise, you will need: 

• Printer that accepts invisible ink cartridges; not every printer will do. I have used VersaCheck over and over, and the products are as good as their service. If you click on the Invisible UV Flourescent Ink option in their top navigation, it will take you to a page where you’ll have 3 options for a printer manufacturer. I bought an HP, but they also have ink for some Epson and I5022 models. Once you specify your printer, choose the cartridge you know works in your printer or choose your printer to see available cartridges. For example, my HP Deskjet 3755 uses a 65 cartridge.

• Invisible ink cartridges. See instructions above to ensure you have cartridges that will work with your printer.

• (Optional, but recommended) Stealth paper. As I understand it —and I believe it—stealth paper has been designed to reveal ultra high contrast images or text when a UV flashlight is used. This isn’t required, but for $30, if you’re buying ink from VersaCheck anyways, I’d opt for the stealth paper.

• UV flashlights. This is another are where I wouldn’t skimp, and there are reasonable options for $10/ea of less, including here at VersaCheck. The $10 light key chain is fine, no need to splurge on a $20 option. You can buy a 4-pack of the flashlight I use for $16 at Amazon. Just remember, you also need to buy batteries!

Technique

The process of creating your invisible ink document is straightforward. Print the invisible part using the printer and invisible ink, and print your exposed words or graphics in a regular printer. I haven’t noticed if there’s any different printing the visible stuff first and then the invisible ink over it, or vice-versa. Typically, because the dinners take place at different restaurants with different logos and menus, I print the visible ink first so I can try to align any of the hidden messages between the text so it’s easily seen.

If you want to execute it the way I do at a dinner, print the restaurant’s logo in black ink at the top of the page and print the menu with plenty of space between courses as that will be a good place to hide messages. Print.

Then, open a separate document, add in whatever hidden messages you want, and try to arrange and align them so they do not overlap with the visible ink. Make sure you feed the paper in the proper way, and print your document using your invisible ink printer.

To execute, think about where your hidden message can be hiding in plain sight. Should your even be 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.

I typically hand out the UV flashlights with a helper just before it’s time to use it; place it on the table before things start and 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

The UV flashlight can be a souvenir! We considered printing “The Dark Funnel” on them for the 6sensory Supper, but it was one of those “the juice isn’t worth the squeeze” things. If invisible ink plays a prominent role in your event, consider branding it. If the message you’ve hidden is something you hope they read later, or share with co-workers, most people don’t have a UV flashlight, so best to gift it to them. On the other hand, there isn’t much for one to do at home with a UV flashlight except illuminate pet pee, so it’s utility as a gift is a tough sell. At 6sense, we let guests take the flashlights home, most do, a few leave it, we grab any left behind to use at the next dinner.