Basics of pigment technology

Learn about the basics of effect pigments. Their versatile pearlescent effects are based on the simple natural phenomenon of refraction.

Play with light

Few things are as versatile and colorful as pearlescent pigments.Thanks to their particular layered structure, light is reflected at different levels in the pigment. The reflected waves interfere with each other, causing amplification or cancellation. Depending on the structure of the layers in each case, this effect creates the brilliant interference color that gives the pigments their unique character.

Other pigment types

The effects pigments industry uses three key pigment classes: absorption pigments, metal effect pigments, and pearlescent pigments. We are familiar with absorption pigments from watercolor paints, for example. They represent "true" colors, as they absorb part of the light that hits them and scatter the rest. This phenomenon gives them their own body color. In contrast, silver metal effect pigments reflect almost all the light like lots of tiny mirrors. This gives them their great surface luster, which is sometimes considered dazzling.

Behind the attractive shimmer of pearlescent pigments is the simple process of refraction. At boundary layers, such as between air and glass, white light is broken up and divided into its components – the colors of the rainbow. The greater the difference between the refractive indexes of the adjacent materials, the stronger the refraction. Depending on the angle at which the light hits the boundary layer, it may be completely reflected or may pass through unchanged.

A piece of nature at its core: mineral mica
Mineral mica is a natural inorganic pigment. The mineral is the starting material for some of our effect pigments. After extraction, it is cleaned, ground, and then coated with one or more metal oxides in a precipitation process. The result: a layer-substrate pigment that interacts with light in a specific way with called interference. The result is a specific interference color, depending on the thickness of the metal oxide. A wide variety of effects can be achieved, from matte shimmer similar to that of pearl or mother of pearl, to interference looks with significant shimmer in all colors of the rainbow.

Innovative substrates for novel effects
The combination of the substrate and coating is key to the look of every effect pigment. A transparent substrate is an important pre-condition for the perfect interaction between the light and the pigment. Natural mica was just the start –today it is possible to artificially produce transparent substrates with similar properties. By coating them with metal oxides, completely new effects can be achieved, far beyond the options offered by natural mica. The innovative substrates include synthetically produced aluminum oxide (Al2O3) platelets, silicon dioxide (SiO2) platelets, and glass platelets made from calcium aluminum borosilicate.

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