Färgskiftningspigment

Färgskiftningspigment, also known as iridescent or dichroic pigments, are a type of colorant that changes color depending on the angle of light and the viewing perspective. This phenomenon is achieved through a layered structure, often composed of thin films of transparent materials like metal oxides. These layers are precisely controlled in thickness to interfere with light waves. When light strikes the pigment, it is reflected and refracted at different interfaces within the layered structure. The specific wavelengths of light that are reinforced or canceled out depend on the angle of incidence and the thickness of the layers, resulting in the perception of different colors.

The primary mechanism behind färgskiftningspigment is thin-film interference. Similar to how a rainbow appears on a soap bubble or an oil slick, the light waves reflecting off the top surface of each layer interfere with the light waves reflecting off the bottom surface of that same layer. Constructive interference occurs for certain wavelengths, making those colors appear brighter, while destructive interference cancels out other wavelengths. By altering the viewing angle, the path length of the light through the layers changes, leading to different interference patterns and thus different perceived colors.

Färgskiftningspigment find applications in various industries. They are commonly used in automotive paints to create captivating, multi-hued finishes. In cosmetics, they are incorporated into eyeshadows, nail polishes, and lipsticks to add shimmer and dynamic color effects. The security printing industry also utilizes these pigments in banknotes and official documents to provide a visual authentication feature, as replicating the precise color-shifting properties can be difficult. They are also found in art supplies, plastics, and textiles to create visually striking and unique designs.