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.

How It's Made: Five-Layer Structure