Japanese tissue
Encyclopedia
Japanese tissue is a thin, strong paper
made from vegetable fibers
. Japanese tissue may be made from one of three plants, the kozo plant
(Paper Mulberry tree), the mitsumata shrub and the gampi tree. The long, strong fibers of the kozo plant
produce very strong, dimensionally stable papers, and are the most commonly used fibers in the making of Japanese paper (washi). Tissue made from kozo, or kozogami (楮紙), comes in varying thicknesses and colors, and is an ideal paper to use in the mending of books. The majority of mending tissues are made from kozo fibers, though mitsumata and gampi papers also are used.
The gampi plant is used in the manufacture of the following papers:
The mitsumata plant is used in the manufacture of the following papers:
, then stripped of their bark and hung in the sun to dry. At this stage in the process, it is known as kuro-kawa, or black bark.
To make paper, the black bark must be converted into white bark. The stored black bark is soaked and then scraped by hand with a knife to remove the black outer coat. It is then washed in water and again placed in the sun to dry.
White bark is boiled with lye
for about an hour, then left to steam for several more hours. At this point, it is rinsed with clear water to remove the lye. Then, it is stream bleached
(kawa-zarashi). The fibers are placed in a stream bed around which a dam
is built. Clean water is let in periodically to wash the fibers. Alternatively, the fibers may be bleached using a process called small bleaching (ko-arai). In this case, it is first placed on boards and beaten with rods before being placed in a cloth bag and rinsed in clear running water.
Impurities
are removed after bleaching though a process known as chiri-tori. Any remaining pieces of bark, hard fibers or other impurities are picked out by hand or, in the case of very small pieces, by the use of pins. The remaining material is rolled into little balls and the balls are then beaten to crush the fibers.
After being beaten, it is common for the kozo fibers to be mixed with neri, which is a mucilaginous
material made from the roots of the tororo plant
. The neri makes the fibers float uniformly on water and also helps to "...slow the speed of drainage so that a better-formed sheet of paper will result." (Narita, p.45)
A solution of 30 percent pulp and 70 percent water is then mixed together in a vat. Neri may also be added to the vat. Nagashi-zuki, the most common technique for making sheets of paper, is then employed. The mixture is scooped on a screen
and allowed to flow back and forth across the screen to interlock the fibers. This process is ideal for forming thin sheets of paper. The other technique for making paper, tame-zuki, does not use neri and forms thicker sheets of paper.
The sheet of paper is placed on a wooden board and dried overnight, then pressed the next day to remove water. After pressing, the sheets are put on a drying board and brushed to smooth them. They are dried in the sun, then removed from the drying board and trimmed.
may be used on any overlapping surfaces in the tear to help hold it together during the mending process.
A strip of tissue is torn away from the main sheet using a water tear. This is done by wetting the paper along the area to be torn and then pulling sideways with the fingers to separate the strip from the rest of the sheet of tissue, so that it will have feathered edges. The fibers in these feathered edges will allow the tissue to have a firmer hold on the mended paper and also to blend in with it once dried.
Paste is applied to one side of the tissue strip, from the center outward. The tissue is then placed, paste side down, on the tear, leaving a little bit of the mending tissue hanging over the edge. This bit will be trimmed off after the mend dries. A dry brush
is used to smooth the tissue over the tear, again, from the center outward. The mended page is placed between layers of PET film
or glass
board, blotting paper
, and reemay (to keep the paste from sticking to the blotting paper), then weighted and left to dry.
Japanese tissue should be water torn in the same process as described above, in a width and length sufficient to cover the hinge of the book with about 3/8 inch extension over the sides. Paste should be brushed on to the tissue, from the center outward, transferred to the hinge and then brushed down with a dry brush.
A sheet of PET film is placed to prevent the hinge from sticking together and it is weighted until it dries.
Paper
Paper is a thin material mainly used for writing upon, printing upon, drawing or for packaging. It is produced by pressing together moist fibers, typically cellulose pulp derived from wood, rags or grasses, and drying them into flexible sheets....
made from vegetable fibers
Fiber
Fiber is a class of materials that are continuous filaments or are in discrete elongated pieces, similar to lengths of thread.They are very important in the biology of both plants and animals, for holding tissues together....
. Japanese tissue may be made from one of three plants, the kozo plant
Paper Mulberry
The Paper Mulberry is a tree in the family Moraceae, native to eastern Asia. Other names include Dak, Halibun, Kalivon, Kozo, and Tapacloth tree.It is a deciduous tree growing to tall...
(Paper Mulberry tree), the mitsumata shrub and the gampi tree. The long, strong fibers of the kozo plant
Paper Mulberry
The Paper Mulberry is a tree in the family Moraceae, native to eastern Asia. Other names include Dak, Halibun, Kalivon, Kozo, and Tapacloth tree.It is a deciduous tree growing to tall...
produce very strong, dimensionally stable papers, and are the most commonly used fibers in the making of Japanese paper (washi). Tissue made from kozo, or kozogami (楮紙), comes in varying thicknesses and colors, and is an ideal paper to use in the mending of books. The majority of mending tissues are made from kozo fibers, though mitsumata and gampi papers also are used.
Forms of Japanese tissue
The kozo plant is used in the manufacture of the following papers:| Paper | Composition | Description and use |
|---|---|---|
| Goyu | 90% kozo | This paper is used mainly for printing and for the hinges of mounting paper materials. |
| Hosokawa ohban | 100% kozo | This is heavier than other Japanese papers and is used as a backing for documents and maps. |
| Kaji | 100% kozo | This lightweight paper is used for conservation processes. |
| Kizukushi | 100% kozo | This paper is used for mending. |
| Misu | 100% kozo | This paper is used in conservation processes. |
| Okawara | 100% kozo | This paper is also used in conservation. |
| Sekishu | 80% kozo | This paper is used for printing and in conservation. |
| Sekishu kozogami mare | 100% kozo | Used in mending. |
| Sekishu kozogami turu | 100% kozo | Used for all types of mending. |
| Udagami | 100% kozo | This opaque paper is used for mending artworks on paper. |
The gampi plant is used in the manufacture of the following papers:
| Paper | Composition | Description and use |
|---|---|---|
| Sekishu Torinoko Gampi | 100% gampi | This soft, silky paper looks as if it is glazed and is used for mending and conservation of artworks on paper. |
The mitsumata plant is used in the manufacture of the following papers:
| Paper | Composition | Description and use |
|---|---|---|
| Kitakata | Mitsumata and sulfite pulp | This silky paper is buff in color and is used for mending older books and documents. |
How it is made
Japanese tissue paper is a hand-made paper. The inner bark of the kozo plant is harvested in the fall and spring, with material from the fall harvest being considered better quality. Bundles of kozo sticks are steamed in a cauldronCauldron
A cauldron or caldron is a large metal pot for cooking and/or boiling over an open fire, with a large mouth and frequently with an arc-shaped hanger.- Etymology :...
, then stripped of their bark and hung in the sun to dry. At this stage in the process, it is known as kuro-kawa, or black bark.
To make paper, the black bark must be converted into white bark. The stored black bark is soaked and then scraped by hand with a knife to remove the black outer coat. It is then washed in water and again placed in the sun to dry.
White bark is boiled with lye
Lye
Lye is a corrosive alkaline substance, commonly sodium hydroxide or historically potassium hydroxide . Previously, lye was among the many different alkalis leached from hardwood ashes...
for about an hour, then left to steam for several more hours. At this point, it is rinsed with clear water to remove the lye. Then, it is stream bleached
Bleach
Bleach refers to a number of chemicals that remove color, whiten, or disinfect, often via oxidation. Common chemical bleaches include household chlorine bleach , lye, oxygen bleach , and bleaching powder...
(kawa-zarashi). The fibers are placed in a stream bed around which a dam
Dam
A dam is a barrier that impounds water or underground streams. Dams generally serve the primary purpose of retaining water, while other structures such as floodgates or levees are used to manage or prevent water flow into specific land regions. Hydropower and pumped-storage hydroelectricity are...
is built. Clean water is let in periodically to wash the fibers. Alternatively, the fibers may be bleached using a process called small bleaching (ko-arai). In this case, it is first placed on boards and beaten with rods before being placed in a cloth bag and rinsed in clear running water.
Impurities
Impurity
Impurities are substances inside a confined amount of liquid, gas, or solid, which differ from the chemical composition of the material or compound.Impurities are either naturally occurring or added during synthesis of a chemical or commercial product...
are removed after bleaching though a process known as chiri-tori. Any remaining pieces of bark, hard fibers or other impurities are picked out by hand or, in the case of very small pieces, by the use of pins. The remaining material is rolled into little balls and the balls are then beaten to crush the fibers.
After being beaten, it is common for the kozo fibers to be mixed with neri, which is a mucilaginous
Mucilage
Mucilage is a thick, gluey substance produced by most plants and some microorganisms. It is a polar glycoprotein and an exopolysaccharide.It occurs in various parts of nearly all classes of plant, usually in relatively small percentages, and is frequently associated with other substances, such as...
material made from the roots of the tororo plant
Dioscorea opposita
Dioscorea opposita is a type of yam that may be eaten raw....
. The neri makes the fibers float uniformly on water and also helps to "...slow the speed of drainage so that a better-formed sheet of paper will result." (Narita, p.45)
A solution of 30 percent pulp and 70 percent water is then mixed together in a vat. Neri may also be added to the vat. Nagashi-zuki, the most common technique for making sheets of paper, is then employed. The mixture is scooped on a screen
Sieve
A sieve, or sifter, separates wanted elements from unwanted material using a woven screen such as a mesh or net. However, in cooking, especially with flour, a sifter is used to aerate the substance, among other things. A strainer is a type of sieve typically used to separate a solid from a liquid...
and allowed to flow back and forth across the screen to interlock the fibers. This process is ideal for forming thin sheets of paper. The other technique for making paper, tame-zuki, does not use neri and forms thicker sheets of paper.
The sheet of paper is placed on a wooden board and dried overnight, then pressed the next day to remove water. After pressing, the sheets are put on a drying board and brushed to smooth them. They are dried in the sun, then removed from the drying board and trimmed.
How it is used
Japanese tissue is used in the conservation of books and manuscripts. The tissue comes in varying thicknesses and colors, and is used for a variety of mending tasks, including repairing tears, mending book hinges, and reinforcing the folds of signatures (the groups of pages gathered and folded together at the spine) or for reinforcement of an entire sheet through backing. The mender will select a piece of Japanese tissue that closely matches the color of the paper being mended, and chooses a thickness (weight) suitable to the job at hand.Mending tears
First, Japanese tissue in a color close to that of the paper to be mended is chosen. The tear is aligned and pasteAdhesive
An adhesive, or glue, is a mixture in a liquid or semi-liquid state that adheres or bonds items together. Adhesives may come from either natural or synthetic sources. The types of materials that can be bonded are vast but they are especially useful for bonding thin materials...
may be used on any overlapping surfaces in the tear to help hold it together during the mending process.
A strip of tissue is torn away from the main sheet using a water tear. This is done by wetting the paper along the area to be torn and then pulling sideways with the fingers to separate the strip from the rest of the sheet of tissue, so that it will have feathered edges. The fibers in these feathered edges will allow the tissue to have a firmer hold on the mended paper and also to blend in with it once dried.
Paste is applied to one side of the tissue strip, from the center outward. The tissue is then placed, paste side down, on the tear, leaving a little bit of the mending tissue hanging over the edge. This bit will be trimmed off after the mend dries. A dry brush
Brush
A brush is a tool with bristles, wire or other filaments, used for cleaning, grooming hair, make up, painting, surface finishing and for many other purposes. It is one of the most basic and versatile tools known to mankind, and the average household may contain several dozen varieties...
is used to smooth the tissue over the tear, again, from the center outward. The mended page is placed between layers of PET film
PET film (biaxially oriented)
BoPET is a polyester film made from stretched polyethylene terephthalate and is used for its high tensile strength, chemical and dimensional stability, transparency, reflectivity, gas and aroma barrier properties and electrical insulation.A variety of companies manufacture boPET and other...
or glass
Glass
Glass is an amorphous solid material. Glasses are typically brittle and optically transparent.The most familiar type of glass, used for centuries in windows and drinking vessels, is soda-lime glass, composed of about 75% silica plus Na2O, CaO, and several minor additives...
board, blotting paper
Blotting paper
Blotting paper is a highly absorbent type of paper or other material. It is used to absorb an excess of liquid substances from the surface of writing paper or objects. It is also commonly used as a beauty tool to absorb excess oil from the skin.-Manufacture:Blotting paper is made from different...
, and reemay (to keep the paste from sticking to the blotting paper), then weighted and left to dry.
Mending hinges
This is another task in which Japanese tissue is often used. In some cases, the first step may be to tip in (that is, add with a thin strip of adhesive) a flyleaf to become the base for the attachment of the hinge mend, if the original flyleaf is not well attached. A small support the height of the spine should be placed to eliminate stress on the hinge.Japanese tissue should be water torn in the same process as described above, in a width and length sufficient to cover the hinge of the book with about 3/8 inch extension over the sides. Paste should be brushed on to the tissue, from the center outward, transferred to the hinge and then brushed down with a dry brush.
A sheet of PET film is placed to prevent the hinge from sticking together and it is weighted until it dries.
Reattaching signatures
In the case where an entire signature (a folded sheet of paper forming several pages, or leaves, of a book) has come out, it may be reinserted by being sewn first onto a strip of Japanese paper, and then by pasting into the book along the newly-formed hinge between the Japanese paper and original signature.See also
- Preservation: Library and Archival Science
- Japanese paper
- Paper mulberryPaper MulberryThe Paper Mulberry is a tree in the family Moraceae, native to eastern Asia. Other names include Dak, Halibun, Kalivon, Kozo, and Tapacloth tree.It is a deciduous tree growing to tall...