When it comes to card cheating, Marked poker cards are the most common and useful device. These markings are invisible to the naked eye and can only be read by specific poker cheating devices such as a poker analyzer. Besides back markings, there are also side-markings. There are different types of these marks, and each type is used for a different purpose in gambling. Some have a barcode, some are invisible ink, and others are tinted. Some are visible only to a particular camera and others require special glasses or contact lenses. The main purpose of Marked poker cards is to help players know what cards their opponents have, which can improve their odds of winning.
The earliest forms of marked playing cards were quite crude, often involving crimps and bends in the cards. Later, the use of chemicals or pigments to alter the card designs came into play. Cheaters would add or remove lines and patterns from the backs of the cards, and some even hid symbols in the corners. These early methods were crude, but effective. They could be detected by performing the gambler’s riffle test, which requires looking carefully at a deck of cards while they are being riffled. This technique is not as effective for detecting marks made using juice and luminous techniques, however.
Since the earliest days of gambling, people have sought to mark cards in order to gain an advantage in card games. While it is illegal to mark cards in casinos, it does happen, particularly in home games and private clubs where collusion is possible. The risk of being caught in a brick-and-mortar casino is low, as the gambling establishment has sophisticated surveillance procedures in place. But the threat of being cheated in a home game is far greater, as there are few rules to prevent such practices.
There are several ways to mark a pack of cards, including using juice, luminous, and barcode. Juice is a method in which the marks are hidden on the sides of the card, making them difficult to see. It is usually applied to the face of the cards, but some marks are also placed on the backs. This method is effective because it is undetectable, but it can be spotted by honest players.
Luminous markings on the back of the cards are invisible to the human eye, but can be detected by a variety of devices, such as infrared detectors and poker analyzers. Luminous markers are also available as eyewear, such as invisible ink contact lenses and gambling sunglasses. These are comfortable and discreet, and can be worn without drawing attention from other players.
Another way to mark cards is with a laser pointer. This is not as effective as a marker, but it can be used to highlight certain cards or indices, such as the ace in a trick-taking game. Alternatively, it can be used to indicate the value of a card, such as by highlighting a king in a rummy game.