Photochromic printing, also known as light-reactive color-changing printing, originally used special dyes that would shift colors when exposed to UV light. The dye's structure would change, revealing different shades and hues.
These days, we use microencapsulation technology to wrap the photochromic dyes in tiny capsules, usually sized between 1 to 10 micrometers. By encapsulating the dyes this way, their lightfastness gets a major boost.
It works by using the principle of converting absorbed UV light into energy, applying light-sensitive color-changing materials to the printing process. After printing, the product changes color when exposed to sunlight or UV rays by absorbing their energy.
Once the sunlight or UV exposure is removed, the colors instantly return to their original state.
