Fournier Marked Deck with Invisible Marks
Fournier marked deck of cards, as the name implies that they are a kind of invisible ink marking on the backside of card deck and cannot be seen by naked eyes.
Fournier marked deck is a classic, well-known and trusted brand of playing cards with a long, rich history.
To detect the back marks of the decks, there are many methods. For example, UV contact lenses and luminous ink glasses can read marks which are luminous and clear. IR camera can read infrared ink cards, etc.