Card marking is one of the methods how to cheat blackjack, and it is basically the process of altering the cards in such a way that the rank, suit or both of them are only apparent to the player who has marked the card. The marks are done on the observer’s side and are usually quite uniform.
Card marking can be done no matter who deals or shuffles the cards. However, some of the more sophisticated scams in the past had also involved other types of manipulative skills in order to place the cards in the right position once the cards have been identified.
How Are Cards Marked?
The earliest card marking attempts were done by creating tiny bumps or blisters, crimps and bends on the cards. When the designs began to appear on the back of the cards, the designs of the cards were altered using scratches, pigments and inks of different types. In the recent years, more enhanced techniques have been used like luminous inks and juice marked cards.
Block out Work and Cut out Marks
Block out work is basically using the same colored ink for coloring the small white areas of the cards to identify them. The cut out work is where the players use a razor to scrap off some of the prints on the cards.
The cards which have been marked with the luminous ink can only be read with the help of special glasses or contact lenses. Earlier the inks used were greenish in color but now special chemicals are used for marking the cards.
Video Luminous Cards
The latest technique which has been used for card marking is the video luminous cards. In this method, the marks that are applied on the cards cannot be read by any individual even through a luminous filter. They can only be read using custom designed filters and electronics and are displayed on a TV monitor to another player who would then transmit or signal the value of the cards to the player at the table.
Players often mark the cards with juice which are only visible to an individual who is trained to read them. No special filters or glasses are needed but some practice would be needed in order to read them. Similarly, shade or tint solution is also used to mark the cards. However, the pattern for the marks would depend on the design on the back of the cards which are being marked.
Daub is basically a special type of paste which is used by the players to mark someone else’s cards sneakily while the cards are being used at the table. This would prevent the need to switching the premarked cards in the deck. Like daub, juice dust is also used to mark someone else’s deck. Juice dust does not dull the finish of the deck of playing cards and it also works on paper as well as plastic cards.
These were some of the basic methods which are used by players for marking cards.