Tengujo:Conservation & Restoration Washi

Tengujo paper is the world's thinnest and strongest Washi paper

Tengujo Washi Paper is manufactured in Japan’s Kochi prefecture in Tengujo-city. Often referred to as “wings of a mayfly,” due to its long and silky fibers. Made from the highest-quality Japanese kozo plant, its fibers make it one of the most distinctive kind of Washi Paper. Indeed, tengujo is the thinnest, most transparent, and incredibly flexible papers in the world.

Tengujo Washi is perfectly suited for all restoration work at the highest level such as partial back-gluing, fixing tears and promoting mechanical stabilization of papers of drawings, books, and fragile written documents. Tengujo Washi has been used for preservation and conservation work for cultural properties such as historical sculptures or paintings across the world.

Restoration Using Tengujo Washi Paper

  1. Repair of weathered paper surfaces
    When paper is not kept under the proper conditions, it can deteriorate. Exposing paper to moisture can result in growing mold and due to the moisture and enzymes from the mold, the paper fibers are decayed where strands or tufts begin to visibly appear on the paper. Tengujo Washi Paper can be used to prevent further weathering of paper by layering it over the paper surface. Even when Tengujo is layered over written document, the text underneath can still be clearly read. This incredibly thin paper that weighs only 2.0 grams per square meter with 0.02 millimeter-thickness is best suited for old document conservation purposes.
  1. Fix deteriorated leather-bound books
    Due to absorption of acidic gases from the atmosphere and excessive dryness, leather cracks and eventually degrades into a reddish-brown powder. By placing Tengujo Washi Paper on the cover of leather-bound materials, further deterioration can be prevented. Because of its thinness, toughness, and flexibility, Tengujo Washi Paper is often used for the restoration of leather-bound materials. In addition, Tengujo Washi Paper is used to fix other wide range of materials that become difficult to use caused by acidity. By simply layering Tengujo Washi on both sides of deteriorated materials, weakened or teared parts, it is all recovered in use. Also, Tengujo Washi’s thinness is convenient for restoring double-sided or colored documents. Made from 100% KOZO plant fiber, the resiliency of Tengujo Washi has been shown to last for thousands of years.
  1. Prevent peeling and loss of surface colors
    In the restoration process of wooden statues, the first step is to handle scratches and stains, and the next step is to prevent from fading and cracking where Tengujo Washi is applied to its surface. Extra colors are added on top of the layer if necessary. In order to perfectly fit with curved lines of the statues surface, this thin, strong, and transparent Tengujo Washi is ideal. All features of wooden sculptures can be preserved naturally because the fibers of Japanese KOZO plants in Tengujo Washi are long, porous, and flexible allowing it to adhere well to the entire surface of the statue. Our own invention of the chlorine-free bleaching technics removes all impurities from the KOZO fibers without using any chemical agents.

Today, in the world’s famous libraries and museums, historical documents and cultural properties that are crucially needed to be restored are increasing rapidly. Tengujo Washi can serve professionals in the restoration field to help save the world history that must be passed through to future generations.

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Materials and Production of Tengujo Washi Paper

The main element of Tengujo Washi Paper is KOZO fiber produced from Japanese mulberry tree. The entire washi-making process depends on how well the KOZO plant is produced. The quality of KOZO plant deeply relates to the natural conditions as well as the age of the tree. Each KOZO has its own unique characteristics, and we use a variety of specific KOZOs in order to meet each customer requirements.

However, a clear difference emerges depending on the technology used in the washi-making process. If chemicals used when boiling the KOZO fibers, the time it takes to process each step, and the uniformity of the fibers and water… these all factors make a difference in the final product. As a result of boiling, pectin and lignin are removed from the fibers, and it comes closer to the point where only fibers remain in the paper-making material. At this point we start applying customized methods to meet each customer’s unique needs.

How to produce Tengujo Washi Paper

Step 1: Boiling KOZO Plant Fibers

After Kozo plants are naturally dried, the first step toward making Tengujo Washi Paper is to boil in a large tank pot. Clean natural water in the region is used for boiling where the pectin and lignin are removed from the fibers, and ready as its paper-making material.

Step 2: Washing to Remove Impurities

Wash to remove every single mote from the fibers.  This is a very important part of the entire process because impurities do not whiten even bleached if remained, and it will appear on paper. Five washing stations with five different workers are required to completely remove impurities.

Step 3: Bleaching Kozo Fibers

At this point, the material is reddish-brown, and it is bleached to be whiteish color where chlorine is usually used. Since chlorine-bleached paper eventually gets yellow, we use our own without-chlorine bleaching method to make paper color unchanged.

Step 4: Mixing the Fiber and Water Ratio

Mix the fibers to be evenly distributed in water solution. The ratio of plant fiber weight to water weight is 1.5 where the material will not sink in water. Then “Neri”, a natural agent to increase thickness of the material, comes in to make it solid enough.

Step 5: Specialized Machines Make Tengujo Paper

The material now flows into the papermaking machine that performs the same operation made back in the days of handmade paper rocking plant fibers to become evenly entwined. Throughout this operation, need to engage in carefully observing and adjusting the size and length of the material.

Step 6: Rolling Finished Tengujo Paper

Now this very thin fibers become rolled into sheets of paper to be the finished paper product. The Kozo fibers are made up of cellulose that is highly water soluble and delicate where need to be dried weeklong at low temperature.

History of Tengujo Paper

The place of origin of this paper was Gifu Prefecture, said to be the birthplace of paper in Japan. In the Muromachi period(1336 to 1573) this paper was already being made, and in the Edo period (1603 to 1867), it had various uses such as sketches for woodblock prints, tracing paper, and also in mounting and backing.

These thin papers began to be developed becoming larger and better quality. In 1880, the experimental forming of large-size Tengujo Washi was made successfully. In the following year, Tengujo Washi with a thickness of 0.03 millimeters was entered into the national market. Recognized as thin, suitable for writing with ink, and durable enough for typewriting.

In this way, Tengujo Washi was first used as typewriter paper, but was also used for napkins, wrapping paper for precious stones, coffee filters, and lens cleaning paper.  Tengujo Washi started being exported and became known as ultimately thin paper worldwide.

However, after World War Ⅱ, the decrease of typewriter usage and the invention of machine-made paper led the decrease in the number of craftsmen. Traditionally-made paper was propped up by a limited demand, and continues a very small existence to this day.

Recently, attention has been paid to the facts that Japanese historical documents and paintings have preserved much longer at higher levels than anything else in other countries. Tengujo Washi became internationally recognized as the finest paper for restoration of cultural properties.  As a result, world-renown cultural properties such as Michelangelo’s wall paintings in the Vatican and works preserved in the Louvre in Paris began to use Tengujo Washi paper for restoration purposes. Today the production of Tengujo Washi paper is stable for large production thanks to machine-made paper technology. This world’s thinnest and strongest paper developed by the dexterous techniques and aesthetic sensibilities of Japanese people has received acclaim over the last hundred years, and it’s continuing even now.

We are seeking distributors and business partners across the world