If the invisible ink is used to mark the back of poker cards, you cannot see any invisible ink markings by our naked eyes unless you wear IR contact lenses or infrared sunglasses. Our company provides luminous ink for customers which can be used to mark different kinds of poker cards, such as Bee marked cards; Copag marked playing cards and so on. Luminous Marked Cards also can be made by poker cards printer. We offer magical ink and technology as well as poker machine to help you to make the markings on the back of cards. You can use our invisible ink to make the markings on the poker cards by yourself.