How Marking Cards With Invisible Ink is Used in Gambling

How to mark cards with invisible ink when playing gambling

Conventional fraudulent gambling techniques involve secret markings on the back of a playing card. Cheaters can use a wide range of materials to create these marks, such as pencils, correction fluid, fingernails and pointed objects. Invisible ink is a more advanced technique. Invisible ink, a transparent coating, creates a light-diffraction when viewed through a special camera or lens. These lenses and cameras can read invisible ink markings that are on the surface of cards. Only a few people have access to them.

The first of these high-tech invisible inks were developed during WWII, when the Allies and Axis powers both struggled to develop inks that were odorless and could only be seen through tinted glasses or revealed by specific chemicals such as iodine or ultraviolet light. Eventually the Allies won the war, but the search for an ideal invisible ink continued into the 21st century.

Today, there are numerous companies that sell decks of playing cards that are marked with invisible ink. Cheaters can also send their own decks to be marked with invisible markings for use in gambling. These companies also offer contact lenses, eyeglasses and modified cameras to see the invisible ink markings.

A video posted on TikTok recently showed a group in a casino trying to play poker using cards that were clearly marked with invisible ink. The whole incident sparked an intense discussion, with many netizens taking a side. Some punters supported the punters while others claimed the host of the game had committed a crime.