Marked cards are one of the oldest tricks in poker and they’ve always been a dangerous threat to casinos. The problem is that card cheaters are constantly developing new ways to fool the system.
The most common types of marked playing cards include:
Magic or Barcode – These are printed with invisible ink, which can only be seen using special glasses or contact lenses. This kind of marking is more practical than luminous markings because it can help players to get a clearer view of the card’s value.
Luminous marked cards are also popular, but they are more difficult to detect by contact lenses and gambling sunglasses. They are based on complicated chemical formulas and optical scientific principles, which makes it almost impossible to spot them.
The newest type of luminous system is called Ultra-Luminous, which is much more effective than the original luminous systems.
Other kinds of marked cards are:
Juice deck – These use shade technology to mark certain cards, which is the result of printing with lighter or darker ink. These marks are often harder to see, require low lighting conditions, and are less easily detected by the gamblers’ riffle test.
Daub – This method relies on a special paste that is applied to the back of a deck while the cards are being played. It can be used to quickly and inexpensively mark a player’s own deck, or to switch in to a pre-marked deck while being watched.
Another method of card marking is block-out work. This technique uses the same ink as the back of the cards, but in a manner that narrows the lines or creates white figures on the backs of the cards. This is a more complex way to mark a deck, and requires more skill than simply bending the cards.
The most important feature of block-out work is that it can only be done by a professional. It can also be very difficult to learn how to read the marks, especially if you don’t have any previous experience.
There are also other techniques for card marking, which can be difficult to detect, such as tampering with the cards’ back patterns and adding markings to the face of the card. The best technique for detecting this kind of marking is to perform the gamblers’ riffle test and look at the back of the card while it is being riffled. This technique works best for identifying cards marked with juice and luminous methods, but is not as effective for detecting other types of marking.