Marked cards for sale are playing cards that have secret markings on the backs or sides to help magicians or poker cheaters identify the suit or value of a card quickly and accurately. These markings can be read in various ways, including by using invisible ink, scanner cameras or glasses. Some marked decks are made with special chemicals that add luminous marks on the cards. These can be read using light-sensitive devices like infrared contacts or gambling sunglasses. Others use tint solutions that are only visible to a trained eye.
Historically, people used many techniques to mark playing cards to improve their odds of winning at card games and magic shows. Some of these were fairly sophisticated and involved bending the cards or altering their design. Some marks were more subtle, like crimps or tiny pinprick bumps called “blisters”, which resemble Braille script. In recent years, players have begun to mark their playing cards using a variety inks, pigments, and scratches. These methods could be dangerous and required a partner who was trusted to read them.
A recent innovation was the creation a deck of playing cards that could be marked in real time, even as they were being played. This process is called juice-marking and only a person with the right skills can see it. The mark is usually just a small tint or color on the card. It can vary depending on the back design.
There are other ways to mark playing cards, such as block-out work, scroll work and shade or tint work. These methods require a partner with a high level of skill to read the markings. They also allow for subtler markings on the cards, such as coloring in white birds in the back design.
A special paste can also be used to mark a deck. It can be applied immediately or even while playing the cards. This method is called daub and can be very effective, although it does have some limitations. For example, it can be difficult to properly apply the daub and can leave a sticky residue on the cards that can interfere with their playability.
A final type of marked deck is one that uses a video-luminous marking system to mark the cards. This is a more expensive and advanced version of marked cards. It offers several advantages over other types. One of the advantages is that a person can read the marks by wearing a pair custom-designed glasses with filters. This is much more convenient than filtered sunglass. Additionally, the cards can be recorded and played back later, which is helpful for analyzing the outcome of a game or looking for signs of collusion between players. A video-luminous marked card deck can be used for a variety games and magic tricks.