What is Optically Variable Ink?

Optically Variable Ink (OVI) is a specialized security ink that changes color when viewed from different angles. This effect is achieved through multi-layer thin-film interference structures within the ink, where each layer's thickness is precisely controlled to reflect different wavelengths of light at varying angles.

Unlike conventional inks that rely on pigment absorption, OVI's color originates from light interference. When light strikes the ink surface, it reflects and interferes between multiple thin film layers, creating vibrant iridescent effects with smooth color transitions as the viewing angle changes.

Core Technology Principles

The core technology of optically variable ink is based on thin-film interference. The ink contains microscopic multi-layer flake pigments consisting of alternating high and low refractive index materials, with each layer measuring only a few hundred nanometers thick.

As light passes through these multi-layer structures, partial reflection occurs at each interface. These reflected light waves interfere with each other, enhancing certain wavelengths while diminishing others, producing specific colors. Since viewing angle changes affect the optical path difference, the perceived color shifts accordingly, creating dynamic visual effects.

Application Fields

Currency & Security Documents: Over 100 countries worldwide use OVI for banknotes and important documents, providing the highest level of security protection.

Luxury Packaging: High-end cosmetics, spirits, watches, and other products utilize OVI to enhance packaging luxury and uniqueness.

Brand Protection: Leading brands use OVI on authentic labels, helping consumers easily identify genuine products and combat counterfeiting.

Creative Design: Designers employ OVI to create dynamic visual effects for artworks, bookbinding, and premium promotional materials.