Observation of visual texture of metallic and pearlescent materials

Abstract

AbstractWe have investigated the visual texture properties of effect coatings. The key question addressed in this work is how the visual texture properties of effect coatings can be visually assessed in a reproducible way.We show that it is possible to define two important visual texture parameters: Diffuse Coarseness and Glint Impression. These two parameters describe the visual texture under two different illumination conditions: diffuse and directional lighting, respectively. Strict definitions of these illumination conditions were found to be crucial when discussing visual texture of effect coatings. For each of these two visual texture parameters, experiments were set up, and observation procedures were designed that standardize the observation conditions. Visual tests were performed on both visual texture parameters. We found good results in terms of observer‐repeatability and observer‐accuracy. Our results show that if the visual texture of effect coatings needs to be visually characterized under different illumination conditions, such as different light booths or changing weather conditions, both diffuse and directional illumination should be included separately. © 2007 Wiley Periodicals, Inc. Col Res Appl, 32, 256–266, 2007