Fall 1995: Papermaking Equipment and Process

The basic papermaking equipment can be roughly divided in to the vat (suki bune) and mould (suketa). The vat is usually made from pine or cedar but a stainless steel liner is added for durability. On the sides of the vat are the supports for the special device (maguwa). These are also used to hold the mould out of the way while mixing with the maguwa.

The Japanese style papermaking mould consists of two parts. The specially made flexible removable screen (su) is made of fine bamboo strips held in place by silk threads. The silk threads are treated with persimmon tannin for wet strength. The number of bamboo strips per centimeter varies according to the kind of paper to be made. The hinged wooden frame (keta) holds the screen in place and is usually made from Japanese cypress.

Papermaking Process:
There are three basic steps in forming a sheet of washi using nagashizuki or flowing method of papermaking. This method is very different from the tamezuki or accumulation method of making paper. The tamezuki method is the Japanese term for the western style papermaking. 

The first step is the kakenagashi or ubumizu. The first scoop if a shallow dip that is quickly flowed across the surface of the screen to form the face or front of the sheet of paper. The excess pulp is allowed to flow over the far edge of the mould. The rapid movement prevents any hard particles from settling on the screen surface. 

The next step is called choshi. This consists of a deeper scoop into the vat and the pulp flows over the screen several times before any excess is allowed to flow over the far edge. This step is repeated several times until the desired thickness is achieved. The movement of the pulp mixture on the screen surface varies according to the kind of paper being made. 

There is an overhead bamboo suspension system that helps to counterbalance the weights of the pulp mixture on the screen surface. This makes it easier to move the mixture over the surface. 

The screen with the completed sheet of paper is then removed from the mould and couched (removed from the screen) onto the shito (special stand that hold the post of newly made papers). The screen is aligned using the placement guides and carefully lowered onto the previously made sheet in such a manner as not to trap any air between the papers. The screen is then removed by lifting the edge nearest the papermaker, then it is lifted away from the papermaker. 

The post of completed papers is left overnight to drain naturally. Then it is carefully pressed, lightly in the beginning then gradually more pressure is applied in order not to damage the paper. The post is pressed for about 6 hours until about 30% of the moisture is removed. 

The pressed sheets are then removed one by one from the post and brushed onto boards to steam heated surfaces to dry. Pine, Japanese horse chestnut, etc. are used for drying boards. The best wood for drying boards is ginkgo. The smoothness of its wood and the rarity of such large trees makes it a very valuable wood for drying boards.

The drying method (natural or mechanical) affects the finished paper. When thick paper is dried mechanically, the surface easily becomes fuzzy so natural drying is preferred.

The finished paper may be sized or coated with dosa (a mixture of potassium alum and animal glue that reduces ink bleeding), konnyaku (a starch derived from the root of the Amorphopallus konjac), or kakishibu (persimmon tannin). It may also be dyed with chemical or natural dyed or textured to make paper like momigami (a randomly wrinkled paper) or chirimen gami (a crepe textured paper). The papers are given a final check before being made available for sale.