The paper is made from the inner fibrous bark of several native plants. The Mulberry (Kozo) bush produces very long and strong fibres and produces papers like “hosho”, this is the most popular fibre producing 90% of all washi. The Mitsumata shrub also has strong fibres that are also soft; it also has a natural coloured lustre. Mitsumata can be more expensive as a plant may only produce 4/6 harvests before a new shrub is needed. The Gampi bush has very long and shiny fibres, which are also very tough. The final effect on a sheet of paper is a beautiful natural sheen. Gampi paper is excellent for archiving, as it is very strong, easily written on and repels insects. It is also a very rare shrub in the wild, no possibility of cultivating it; this makes the paper one of the most expensive. New fibres are now being used to produce washi like bamboo, as well as additions from flowers and other plant material used to decorate papers.
The other most important element in the paper-making is the water. This traditionally comes from mountain streams in the winter months and produced by farmers when then they can’t work in the fields and the ice cold water is free from impurities. The colder the water the firmer and stronger the paper is; in the summer month’s humidity can rot the paper and will produce a limp sheet. Paper makers have been known to add snow to the paper making process to make the water as cold and pure as possible.
The fibres are striped from the inner-bark and are soaked or steamed in a solution until they become soft. They are then washed in water or snow to clean them again, before being beaten. This is usually with a wooden beater specially made for the job. The fibres are regularly turned to make sure they are evenly beaten until all the fibres are separated and even.
A slurry of water, fibres and tororo (sticky plant extract) is then made, which a mat or screen called a “Su” is plunged into. This is then brought out with a thin layer of sediment captured. The Su is shaken in all directions to interlock the fibres in a thin even later. The master can then plunge again to create a thicker sheet of paper.
These sheets of paper are then left to dry either outdoors when weather permits or indoors on a hot plate. Each sheet of paper is separated out by a strand of straw or string to stop the sheets sticking together and stacked to dry.