Invisible ink, which is a magic ink solution, once you use it to write anything, they cannot be saw by people naked eye so that it can protect your secret easily. And the invisible ink of GS is the best choice for you. GS has different ink for marked cards contact lenses or infrared playing cards scanner.
However, the card marking ink you use for contact lenses, only write on the red cards can you get the ideal effect, and playing under yellow light will be better. While if you use the one for infrared playing cards scanner, both marked cards contact lenses or infrared poker scanner can read them.
The playing cards invisible ink of our company are mainly used for marked cards printer machine, that means it will perform well when working with printer. Of course, we also can provide special luminous ink for contact lenses that can read playing cards for you to mark poker manually.