Towards a practical metric of surface gloss for metallic coatings from automotive industry

Abstract

The specular gloss of metallic coatings from the automotive industry can be well measured by current glossmeters when the geometry is appropriately chosen from 20°, 60°, and 85°based on the gloss levels observed. However, the measurements are discontinuous and even nonmonotonic at the breakpoints dividing samples into different gloss levels in the whole range, which causes confusion and inconvenience for industry applications. In this study, attempts were made to link the measurements at the three geometries to be continuous monotonically and in the meanwhile to improve the accuracy of estimating visual gloss. A psychophysical experiment based on a magnitude method was carried out to assess the gloss of metallic coatings with different colors and textures. The visually scaled gloss data were compared with spectrophotometric measurements and instrumental specular gloss values under different geometries. With different weighing coefficients for measurements at individual geometries depending on the gloss levels, a model was proposed to describe the visual surface gloss of metallic coatings comprehensively via a practical metric based on the geometry-dependent measurements. In this way, each sample would have a unique overall gloss value highly correlated with its perceptual evaluation over the entire gloss range.

Development of a perceptually uniform physical scale for visual assessment of specular gloss

“…Statistical analysis of our study shows that the STRESS for inter-observer disagreements was less than 25 percent which is comparable to the STRESS of the inter-observer disagreements. Such STRESS values attained are far below the STRESS values reported by other authors using a maximum of 10 observers [29,30].…”

Color difference of yarn-dyed fabrics woven from warp and weft yarns in different color depths

“…A panel of 13 observers participated in the experiment, of whom 6 were females and 7 were males. The color vision of observers was tested using the Farnsworth–Munsell 100 Hue Test, and all observers selected for the study had normal trichromatic vision (Wu et al , 2016). Each observer wore a mid-gray laboratory coat and a pair of gray gloves to minimize color variability of the surroundings during observation and to prevent the samples from being damaged.…”