Measuring Effect Pigments

Today’s exotic color shifting effect pigments causes a change in hue when viewed from different angles. Coatings using these special effect pigments can exhibit a rainbow of colors when seen from different perspective. The change in the brightness and colors is termed as color travel.

The color changes as the illuminating and viewing angles changes, creating a dazzling and dramatic effect. In a typical 45/0 spectrophotometer, the illumination is positioned at 45° and the specular reflection or mirror reflection of this illumination is at 45°. Such spectrophotometers are used for measuring solid colors, but are not suitable for special effect coatings. To measure metallic and pearlescent colors, a multi-angle spectrophotometer or goniophotometer is required.

These multi angle spectrophotometer has multi viewing angles to characterise the effect and research suggests that two near aspecular reflection (-15° and 15°) viewing angles can help capture the data for the rich color changes. Aspecular angle is the difference between the specular reflection angle and the viewing angle.