Why Does Laser Foil Produce Rainbow Effects?

Why Does Laser Foil Produce Rainbow Effects?

When you see that angle-shifting, color-changing metallic brilliance on premium packaging — have you ever wondered how it's made? Is it printed color? A special coating? The answer lives in the microscopic structure of the foil itself.

Those rainbow color-shift effects come from a technology called Interference Lithography: microscopic diffraction gratings are pressed into the aluminum layer of the foil. These gratings have spacings of just a few hundred nanometers — roughly the wavelength of visible light. When light strikes them, different wavelengths are diffracted at different angles, creating the spectrum-shift effect.

Understanding this principle helps you choose the right pattern, set the right processing parameters, and cut through the confusion around the word "laser" in foil terminology.