Many customers asked me that if there is a invisible ink that can mark the cards for contact lenses themselves. The answer is YES. Our company offer you the ink that can help you to mark the red cards for contact lenses, and the red and blue cards for IR camera. If want blue cards marked for contact lenses, better let the cards marked by our factory.
You may ask why? Why blue cards can not? Invisible ink seen under contact lenses is black, so black color face to blue color, it is very hard to be distinguished.
How long can the ink dry? And how long can the ink stay on the cards? The ink can be dry after 5 seconds and can last for more than 3 hours. Very useful ink for you.
The invisible ink can mark both paper cards and plastic cards. Such convenient magic ink, get one immediately!