Cards Trick-secret Marked Cards Revealed
As technology has advanced, so have cheating techniques. Invisible ink systems are still in use today in very sophisticated forms. The biggest advance in recent years has been with the use of optical character recognition (OCR) software that can be built into everyday objects. OCR software reads the cards and talks directly to the players with the earpieces – the only confederate the player needs now is his smartphone, which would not demand a cut of the winnings. Unfortunately for the cheats, if a player suspects the cards are marked and seizes them, the marks can and will be found. The ultimate deck of marked cards is one that can be plainly read by the cheaters, but impossible to detect by anyone after the game. Such a system exists. Using a thermal-imaging camera, it is possible to detect a small heat differential to a very high degree of accuracy. With cameras hidden above the table, a team of cheaters needs only to slightly warm the target cards to make them visible. In a blackjack scenario, where the aim is to beat the dealer by finishing with the hand closest to but not exceeding 21, the high cards would be warmed and the low cards cooled slightly before bringing them to the table.A confederate looking at the output from the thermal camera would know the approximate value of both the top card before it is dealt, and the face of dealer down hole card. The heat eventually dissipates and the entire deck returns to room temperature. At that point the cards are completely immune to any sort of forensic analysis.