Effect of light source distances and illuminances on the gloss perception of papers.

This study examines the human gloss perception of printing papers at various illuminances and distances from a light source to the object's surface. Gloss is evaluated based on not only the intensity of reflected light but also the sharpness of specular highlights. The apparent spread of the reflected light source image, which is also used for gloss evaluations, depends on the distance between the light source and the object's surface. Unlike physical variation of specular image properties, the perception of gloss may exhibit constancy similar to color perception. Our results reveal that illuminance has a strong effect on gloss perception. We found cases where low-gloss samples looked glossier than high-gloss ones-the gloss reversal phenomenon. These results suggest that there is a case in which gloss constancy may not work in every condition.