Yasuhiro Oka

Motion Analysis of the Pounding Technique Used for the Second Lining in the Fabrication of Traditional Japanese Hanging Scrolls

This study focuses on the technique used to adhere the second lining in the fabrication of traditional Japanese hanging scrolls, or kakejiku. We analyzed the motions of both expert and non-expert artisans during the adhesion process, using optical and infrared motion captures. We then conducted a peel test from both samples, and used the results of this test to correlate the motion of the artisan with the adhesive strength of the second lining.

The Load Measurement of the Beating Brush in the Second Lining Procedure

Hanging scroll is a traditional Japanese ornamental art, which includes paintings and calligraphy. Scrolls are unrolled and hung on a wall or in an alcove when displayed and are rolled up and stored in a box. They should hang straight without rippling or warping when unrolled, and be rolled up smoothly and tightly from the bottom when stored. To enable rolling out and hanging scrolls smoothly, the paintings and calligraphy referred to as “main works” are generally backed with traditional Japanese paper and adhered using a paste made from wheat starch. Especially in order to guarantee this flexibility function that enables rolling up smoothly, a type of glue that does not harden after it dries is employed as the adhesive agent for the lining process. But since this glue does not have sufficient adhesive effect, craftsmen employ a traditional technique of pounding the paper with a special “pounding brush” to enhance its adhesive effect. In this study, using pressure measurement films, we considered differences in the techniques of an expert and a non-expert by measuring the pounded area by a brush and the pressure to be applied by pounding with a brush. Through the quantification of the differences of these two subjects, we aim to understand the characteristics of proper pounding technique, to help new craftsmen learn more quickly.

Researching Sounds Generated During the Second Lining Pounding Process

Japanese calligraphy and works of art, which are written and painted on paper and silk, are often lined with Japanese washi paper and strengthened from the reverse side. They are then treated with various binding methods based on the purpose of the item and how it is intended to be viewed. The hanging scroll, which is a perfect example of a binding format, is only displayed when it is meant to be viewed and is hung on an alcove or beam. When it is finished being used, it is rolled up tightly from the bottom and stored in a box. In order to repeatedly roll up and open a hanging scroll smoothly, the hanging scroll is lined with several layers of Japanese washi paper, which are pasted onto the reverse side of the scroll. A paste with a low adhesive strength which has been further diluted is used to prevent the adhesive from hardening after it has dried. The joined surfaces are then pounded with a brush to enhance the adhesion. The level of expertise of this technique is determined by the sound that is generated when pounded using the traditional method. This research measures the sound generated when the joined surfaces are pounded by an expert and a non-expert with the purpose of evaluating the specific features of both sets of sounds.

Electromyography Measurement of Workers at the Second Lining Pounding Process for Hanging Scrolls

Hanging scrolls are a traditional Japanese form of binding and displaying artwork or calligraphy. The scrolls are rolled up from the bottom up and stored in a box, or hung on a wall for display. It is important for the scroll to be able to roll up smoothly without causing any creases when on display. Several layers of Japanese washi paper attached to the back of the scroll make these two functions possible. Wheat starch glue, a weak form of adhesive used to fortify the back, is combined with a technique called “pounding” with the use of a pounding brush, to promote adhesion. In this research, we attached an electromyograph on two subjects – an expert and non-expert binder – to study the movement of their muscles in 9 locations when pounding. Results of this study are expected to help contribute to the acquisition of the binding technique.

Research of Adhesive Effect Enhanced by Pounding Brush on Second Lining Pounding Procedure for Japanese Scrolls

Hanging scrolls are a traditional Japanese ornamental art, which allow paintings and calligraphy to be unrolled and hung on a wall or in an alcove for display, and rolled up and stored in a box. Hanging scrolls should hang straight when unrolled, and roll smoothly for proper storage, without damaging the artwork beneath. For this purpose, scrolls are lined with several layers of Japanese paper, and adhered together with a weak, aged paste made from wheat starch, which gives the paper the flexibility required when the scrolls are rolled up for storage. While this old paste facilitates winding a scroll because it does not become hard even when dried, it does not have sufficient adhesive effect to grip Japanese paper. In order to increase the adhesive power of this aged paste, craftsmen employ a traditional technique of pounding the paper with a special “pounding brush.”This pounding technique is an important part of the fabrication process of hanging scrolls, but it is a difficult task for each generation to pass down the proper pounding technique. This study was intended to verify the effects of the pounding technique on aged paste and Japanese paper. We prepared samples with the pounding technique and investigated their adhesive properties of samples by peel text. In order to verify the importance of this traditional technique and the traditional materials, we compared and analyzed the differences in adhesion between craftsmen of different skill and differences introduced by paste concentration and backing paper quality.Copyright