Luminous Infrared Marked Playing Cards
The process of altering playing cards is known as card marking. This is a very effective cheating method as the marks are apparent only to the conspirator. After the marking process, the cards can be used for magic tricks on one hand, or for cheating in a variety of poker games, on the other. Usually the distinguishing mark or marks are done on the uniform back side of the marked playing cards, and in this way the effectiveness of the cheating is guaranteed. The easiest way to mark probably is called card bending. When using this method, the cheater marks the cards by crimping.
Card marking is often used to cheat when gambling or for card tricks, regardless of who shuffles and deals the cards. Sometimes additional manipulative skills are needed to steer the desired cards into the correct positions. No matter the effectiveness of the card marking, many casinos have adopted a method to prevent cheating. By punching holes through the middle of the cards they sell to tourists, the casinos are trying to protect the game tables, from cheaters who are slipping favorable cards into their hands when playing.