How Does Juice Work?
The juice is a liquid that you dab on the back of playing cards. Bee style cards work best, but others will work as well. (Though you only get a true Juice mark with a Bee deck.)
The Juice is exceedingly easy to apply. Depending on how long you leave the liquid in place, you can create darker or lighter Juice marks. Time tables are given in the manual, as well as the marking system.
There is a true skill to be learned in seeing the lightest marks.
The look of these marks is hard to describe. I think the best example were the 3D posters of a few years back that looked like just a jumble of paint until you unfocused your eyes and relaxed. Then, suddenly a picture would jump out at you.
Juice marks are somewhat the same, though less sophisticated. The harder you look at the back of the card, the harder they are to see. Bright lighting actually makes the marks harder to see! Yet, once a card is treated, and you've learned to see the marks, you can spot them from anywhere in a room.