Medina JM, Díaz JA. Low-frequency correlations (1/f(α) type) in paint application of metallic colors.
OPTICS EXPRESS 2012;
20:17560-17565. [PMID:
23038309 DOI:
10.1364/oe.20.017560]
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Abstract
We examine trial-to-trial variability of color coordinates in automotive coatings containing effect pigments, which are considered a reference paradigm for engineering angle-dependent color effects. We report the existence of correlations that show 1/f - Fourier spectra at low frequencies in all color coordinates. The scaling exponent was lower at near-specular conditions for lightness variations, suggesting a contribution from the deposition of metal flakes in metallic colors. However, the exponent was lower near the specular for blue-yellow variations, suggesting a contribution from chemical pigments in solid colors. These results were independent of the illuminant spectra. The methods employed are useful in the evaluation of industrial color matching among assembly parts.
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