Why invisible ink contact lenses can't see through infrared playing cards

Infrared poker camera is used to read infrared ink marks hidden on the back of playing cards. Infrared ink marked cards are not like invisible ink marking cards that can use with invisible ink contact lenses. Marking with special infrared ink, infrared playing cards need to use with infrared camera.
Infrared poker camera can be installed into many things to help you see through marked playing cards, such as air conditioning infrared camera, ceiling lights lens and cctv marked cards spy camera. Anything above the poker table is a suitable cover for infrared poker camera.

Why invisible ink contact lenses can not see through infrared ink marked playing cards? This is a question that most of customers will ask about. That is because light has different wavelengths. The visible band of human eyes is range from 390 to700nm; when the wavelengths are beyond this band, you have to draw support of special tools. For example, if you want to see infrared wave band, you need to use with infrared camera. And that is the reason why human naked eyes can not see the infrared markings on playing cards, and that is why they need to use with infrared poker camera.