How can we mark a deck of playing cards with invisible ink marks that other poker players can't read?

First of all, you may think of the invisible ink or ink pens, which is the traditional ways that most guys may want to try. In fact, this traditional method is not so practical for the luminous marks of invisible ink may be some degree visible to people with naked eyes.

What is a practical method? Our technicians mark the playing cards with invisible ink by an advanced machine. It's the best method so far and these marked cards are the most safe. This way of marking a card can be studied for professional money making schemes such as poker or magical illusions.