Study on Optical Property of Shoji Papers

In this study, fiber compositions, colors, light reflection characteristics, and light transmission properties for the commercial shoji papers were investigated. The results were as follows. 1) Although the shoji paper predominantly composed of broussonetia-kazinoki (Kozo) contains local aggregations of fibers, the density of the paper was smaller as compared with the shoji paper composed of pulp and/or other fibers. 2) The commercial shoji papers often show a bluish whiteness according to the use of a fluorescent agent. The fastness of the agent to sunlight was not so excellent. 3) The screening effect of shoji paper can be evaluated by measuring its haze value obtained from the transmittance ratio of light. 4) Machinemade shoji papers using rayon, synthetic fibers, binding agents as well as wood pulp are usually produced under hot pressurized conditions. Thus, the surface of the papers tends to become smooth. Accordingly, the machine-made shoji papers reflect light more directly and luster artificially as compared with hand-made shoji papers prepared from broussonetia kazinoki (Kozo).