Abstract
Gold, silver, or bronze are perceived in metallic, glossy surfaces with certain chromaticity ranges. However, it is not known yet how gold depends on the metallic perception. The present study compared the perceptual degree of goldenness and perception of metallic gloss to investigate underlying perceptual mechanisms for gold and metallic gloss. We simulated metallic and non-metallic objects (sphere and Stanford Bunny and 26-faceted polyhedron) by 3DCG to be used as stimuli in the experiments. These metallic and non-metallic images were morphed in luminance to make stimuli with different metallic levels. The luminance of each morphed image was multiplied to make different luminance levels. The same chromaticity, which was estimated as a high degree of goldenness in our previous experiments, was used for all stimuli. The observer carried out the magnitude estimation of goldenness and the surface metallicity, for which the criterion was whether the stimuli appear as metallic surfaces, for the stimuli with 6 different metallic levels and 5 different luminance levels. Although it was confirmed that the degree of goldenness almost correlated with the degree of metallicity, it was found that the degree of goldenness increased with the luminance level of the stimuli, whereas the degree of metallicity did not increase. This result suggests that the perception of goldenness does not totally depend on the metallic perception. Furthermore, this result indicates that goldenness might change depending on illumination level because the luminance level of the stimuli could be regarded as the illumination intensity.