1、Invisible ink
Parts of the book are printed with invisible ink, and children use UV lights to illuminate the hidden patterns in the book, adding to the fun of reading and exploration.
2、Luminous ink
Printing patterns with special luminous ink, after absorbing a certain light source, you can see the bright light in the dark environment.
3、Water-sensitive ink
Water-sensitive ink to cover the content, coated with water can be visualized.
