Glossiness of colored papers and its application to specular glossiness measuring instruments

The glossiness of paper and painted objects is one of the important factors in the evaluation of their manufactured quality. Although the gloss of specimens is judged visually in quality control, specular glossiness measuring instruments now offer a replacement for visual evaluation. However, in evaluation of glossiness in a group consisting of specimens of different colors, the specular glossiness measuring instrument has certain deficiencies, as a result of which the measured glossiness values are not proportional to human evaluations of glossiness (psychological glossiness); however, the instrument is suitable to a group consisting of specimens of similar color. Thus, research intended to obtain suitable measurements of physical glossiness for colored specimens was undertaken. First, an attempt was made to approximate the gloss appearance perceived by the human eye by using a model of the intensity distribution of the light reflected from a specimen surface. Utilizing the obtained gloss appearance, a new physical glossiness is defined and is provisionally named “specular diffusion ratio glossiness” (GSD): The new glossiness is shown to be nearly proportional to the psychological glossiness by the use of the glossiness measuring apparatus developed in this study. In the latter half of this paper, the application of the new glossiness index GSD to currently used specular glossiness measuring instruments is proposed, and its utility is confirmed by using various colored papers. Finally, problems for future research are identified. © 1997 Scripta Technica, Inc. Syst Comp Jpn. 28 (1): 95–112, 1997