Optical characteristics of Japanese porcelain bodies prepared from high plastic clay

Abstract

The absorption and scattering coefficients of porcelain bodies were measured with the aim of improving the optical characteristics of Japanese porcelain prepared from plastic clay. The spectral absorption of the bodies was 0·02-0·07 mm^-1, similar to that of European hard porcelain. It was found that absorption could be lowered by increasing the content of alkali metal. Scattering coefficient, 10 mm^-1 at 380 nm and 3·0 mm^-1 at 780 nm, was much smaller than that of European bodies, which is typical for porcelain produced from Japanese plastic clay. Scattering coefficient varied with wavelength, behaviour which was considered to result mainly from the amount of mullite crystals present. On a reflectance-transmittance diagram, all the data for the Japanese porcelain bodies were on a single curved line, again demonstrating typical optical characteristics for Japanese porcelain bodies produced from plastic clay. Based on these results, a way of improving the whiteness and translucence of Japanese porcelain bodies is discussed.