Towards a practical metric of surface gloss for metallic coatings from automotive industry
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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.
KeywordsGloss Metallic coatings Visual assessment Glossmeter Practical metric
This work was supported by the National Basic Research Program of China under Grant No. 2013CB328802.
- 1.Pointer, M, “A Framework for the Measurement of Visual Appearance.” CIE Publication 175-2006, 2006Google Scholar
- 6.Hunter, RS, Harold, RW, The Measurement of Appearance. Wiley, New York, 1987Google Scholar
- 11.ISO 2813, Paints and Varnishes, Measurement of Specular Gloss of Nonmetallic Paint Films at 20 Degrees, 60 Degrees and 85 Degrees. ISO, Geneva, 1994Google Scholar
- 12.ASTM, Standard Test Method for Specular Gloss, ASTM International, West Conshohocken, 1999Google Scholar
- 14.Lindstrand, M, Gloss: Measurement, Characterization and Visualization-in the Light of Visual Evaluation. UniTryck, Linköping, 2002Google Scholar
- 16.CIE Publication 15:2004, Colorimetry, 3rd ed. Central Bureau of the Commission Internationale de l’Éclairage, Vienna, 2004Google Scholar
- 20.ISO 105, Textiles-Tests for Color Fastness, Part A02: Grey Scale for Assessing Change in Color. ISO, Geneva, 1993Google Scholar