Visual Appearance of Printed Special Effect Colors

摘要

This paper investigates the visual appearance of printed special effect colors that become increasingly popular in high-quality printing. Since traditional colorimetry is insufficient to assess the unique visual appearance of such prints, improved perception-based measures and tolerances are necessary for process control and quality assurance. A prerequisite for developing such measures is a transformation of measurable physical quantities (e.g. Bidirectional Reflectance Distribution Function or Bidirectional Texture Function) into a space of relevant appearance attributes. In this study we determine the latent appearance dimensionality of a selected set of printed special effect colors and analyze suitable attributes for describing its appearance. Samples were produced by screen printing employing 22 special effect inks and two paper grades. A subset of 14 samples was selected showing a high variability with respect to visual appearance, material and spectral reflectance. In a first experiment, subjects rated the difference of the visual appearance between samples. In the second experiment, the magnitudes of twelve reasonable appearance attributes were assigned to each sample. Subsequent statistical evaluations include classical multidimensional scaling and correlation analysis. Our results show that the latent dimensionality of the sample set is at most five. The set of appearance attributes for describing the samples includes the color attributes, one attribute for gloss and one for texture.