Card Marking - Detecting Marked Cards - Shade Technologies

Shade Technologies

• Luminous marked cards - These can only be read by using special gimmicked sunglasses or by wearing contact lenses. The original luminous systems used red lenses and greenish ink on the back of red cards. New luminous technology, called Ultra-Luminous, uses far more sophisticated techniques that are based upon different chemical and optical scientific principles than the original luminous systems.

• Video-luminous marked cards - As stated above, luminous marked cards are designed to be read by the human eye with the use of filtered sunglasses. However, recently, a new generation of luminous technology has become available. Video-luminous uses marks that can not be seen by any human being, even if they are looking through a luminous filter. The marks can only be read by using custom-designed electronics and filters and displayed on a TV monitor in another room to a partner. Then the card values may be signaled or transmitted to the player who needs to know.

Video-luminous does not have to be used for cheating. They may be used for magic or by a poker house or person who may want to analyze a card game after the fact. If collusion is suspected, the recorded images of the marked cards may be played back later to detect any unusual play. If a player consistently folds a good hand when a partner plays a better hand, then it can be assumed that collusion is taking place in the game. Since these marks cannot be seen by the human eye, there is no chance of detection of the marks, even by knowledgeable players, during the game. Often such marked decks will only be introduced by the house when suspected colluders are seated.

• Juice-marked cards - The marks are only visible when a person is trained to read the marks (no filtered sunglasses are required, but some practice is required to read the marks). Glasses can be used to make it easier to spot these marks.

• Tintwork or shade - This technique uses a tint solution to mark cards, but the marking patterns vary depending upon the back design of the cards being marked.

• Daub - A special paste is used by a player to mark someone else's deck, on the fly, while the cards are being used during a game and even while being watched. This eliminates the need to switch in a pre-marked deck of cards.

• Juice dust - An advanced type of daub, it may be used to make an ad-hoc juiced deck. Like daub, it also allows a player to mark someone else's deck, on the fly, while being watched. The main advantages of juice dust are that it will not dull the finish of the cards and that it works on both paper and 100% plastic playing cards.

It is not necessary to mark the entire deck in order to gain an advantage in most types of poker - even marking just one rank (especially the aces) is enough to gain a significant advantage in a game such as Texas hold 'em.