Reading marked playing cards with infrared contact lenses is already a simple way to play a trick on poker game. Then how about with a pair of infrared sunglasses to read invisible ink back marked cards? In fact, it would be a great choice for us if you are not used to wear contact lenses in your daily life. Infrared sunglasses have same work principle as infrared contact lenses.
Our perception of light by our eye has a certain range. To some extent, the light wave beyond this range cannot be recognized by the naked eye, so this object does not exist for us. For example, it is known to us that our marked cards are marked with invisible ink kit and original playing cards via professional printer. As we said that the ink is unreadable to our eyes, so we must use the special tools to read it. Because the ink we applied to mark cards is infrared ink and our eye can’t recognize in the infrared light. It is because of this principle that we processed our normal sunglasses as infrared sunglasses. In the meanwhile, we also plated the glasses with a layer of normal polarized glass to make it look more like normal sunglasses, reducing the suspicion of other players.