How to Detect Invisible Ink Markings on Cards
Invisible ink markings on playing cards is a popular cheating method for card players. These invisible ink markings are transparent on the surface of a card and can only be detected by using special devices, such as a UV illuminator or an infrared (IR) filter. This article outlines a method of image processing for detecting invisible ink printed on the back side of a credit card without using UV illuminators or IR filter.
There are two main types of invisible ink. These are water-based and magic luminous ink. Magic luminous ink is a way to make marked cards visible even after they have dried. Water-based ink is only visible under certain conditions. It needs warmth, a light source, and a specific chemical to be activated and fluoresce.
If you want to mark your own deck of cards, you should know that the best marked cards are ones with no stains. This is because stains will ruin the effect of invisible ink as well as the message written on the cards. Also, the invisible ink on a good quality card is not easily removed. A professional printing technician will ensure that there are no stains and spots on the card when it is printed. Moreover, he will make sure that the invisible printing ink is mixed properly and printed on cards.