CONSERVATION / RESTORATION     'Conservation' and 'restoration' have a difference in meaning. With 'restoration' is meant that the object is restored to its original state. With 'conservation' the object is conserved to the present state to avoid further damages. For instance museum pieces which have a great historical value are mostly conserved with minimal change, On the other hand, objects of private collection are often restored in a bigger extend to regain the original beauty with aged elegance.

From the end of the 17th century urushi was dismantled and used as valuable veneer. In this manner japanning artists developed their own techniques and materials, and these were used for the conservation of urushiware. The point is that this conservation manner with japanning on urushiware led to problems, which will reverberate in the future.
Urushiol is the main substance of urushi which can be used to as adhesive agent, filling, paint, protection and glossing. The main difference between japanning and the original urushi is that the japanning technique makes use of various materials from different origins. This is a critical point. Using urushi for the treatment of the whole object makes the speed of aging simultaneous and well balanced. This is the reason that it is preferable to use materials of the same origin for the conservation and restoration of urushiware.

japanning material
Fig. C1   japanning
material: (as clockwise
from the left top) Paraloid
B-72 /different kinds of
synthetic glue / beeswax

/ animal glue / shellac

Fig. C1  Japanning materials include: shellac, natural resins such as sandarac and copal resin, essential oils, beeswax and paraffin used for coating, filling and glossing, and other purposes. These materials are used for the conservation of urushiware. In the current conservation method, synthetic glue, synthetic varnish (Paraloid B-72), and acrylic colours are used.

plastic piece in an object
Fig. C2   a piece of plastic
Fig. C2  In my experience, even a piece of soft plastic of approximately 4.5 x 2 cm was found in a gap on an urushi panel. One can see that japanning contains materials that differ greatly in both construction and structure. It should be called into question what the effects are of conservation of original urushiware by using japanning materials.

cleaning material 1
Fig. C3   cleaning
products: (as clockwise
from the left top)
petroleum ether / ether /
acetone / 96% distilled
alcohol / ammonia /
distilled water /
petroleum ether / cotton
cloth / cotton rolls /
cotton swabs / brushes /
wooden spatulas
Fig. C3   The products in the figure are used to dissolve the japanning material. Acetone is used for the removal of synthetic resin and synthetic glue. Obstinate dirt and fat are to be undertaken with diluted ammonia-water or petroleum ether. I myself, generally use distilled water and 96% distilled alcohol. They can be used warmed or at room temperature. Cleaning tools used include: soft brushes, cotton swabs, soft cotton cloth, cotton cloth rolls, etc.

cleaning material 2
Fig. C4   whetstones and
knifes: (as clockwise from
the left top) charcoal /
synthetic whetstones /
knives / waterproof
Fig. C4   Items shown in the figure are tools that are used as a last resource for the unavoidable situations where the solvents have not been effective. Traditional charcoal, synthetic whetstones (#1000 - #4000) and sandpaper (#1000 - #2000) are also used. Finer mesh can be gained by abrading two sandpapers to each other. Knives which are used are of various kinds, from specimens shown with sharp cutting edge to round-edged types.

cleaning shellac
Fig. C5   comparison of
cleaning: before and after
Fig. C5   This illustrates the surface undergoing a cleaning with 96% distilled alcohol. The upper half shown is before cleaning, the bottom half is after cleaning. Clearly, the cleaned part has regained its vivid golden colour.
after cleaning shellac
Fig. C6   after cleaning
Fig. C6   Frequently gold grains of the makie-decoration on the urushi surface disappear during the cleaning. But this cleaning process carries the danger of washing away the makie-decoration and fading of the original urushi colours. Had shellac not been applied on the surface, this kind of trouble could have been avoided. 

beeswax under the metal fittings
Fig. C7   wax under the
metal fittings on the
urushi box
Fig. C7   Wax, which is often used as it is an easy material for filling exfoliation and glossing surfaces, can cause irreversible damages to the urushiware. The surface of the aogaizaiku  urushi box is coated with shellac and partly a thin wax layer. Wax fillings were found in the missing parts of the raden  as well as underneath the metal fittings.

The influence of beeswax could be verified by means of a simple test.
Fig. C8 and Fig. C9 show the results of the cleaning experiment of the beeswax on a plain wooden board.
beeswax test 1
Fig. C8   experiment on removing beeswax 1

Fig. C8a 
  A medium hard maple wood of which the upper half is of plain wood and the bottom half is treated with beeswax and left for a few days. Next step was for the beeswax to be warmed till softened and scraped off with a spatula. Then the wood was cleaned with distilled alcohol, acetone, ethanol and petroleum ether. The cleaned part was divided into three equal parts. The left part (a-1) was cleaned as described above; the middle part (a-2) was sanded down after cleaning; and from the right side (a-3) a layer of 0.1mm was scraped off with a knife after cleaning.
Fig. C8b   After being lacquered with kijiro-urushi , the board was left to dry for one night.
Fig. C8c    The bottom-half, that was treated with beeswax, had a lighter colour and seemed half dry. When the whole board was cleaned with petroleum ether, the urushi came off since the urushi had not fixed onto the wood (c-1). The cleaning with solvents and sanding did not make any difference to the results (c-2). The urushi on the right side (c-3) had dried for a large part, except for the parts in which the conducting vessels had let the beeswax through.
Moreover there are white spots visible on the plain upper half of the board (c-4). The beeswax that has made its way through the conducting vessels caused this. This transportation of beeswax occurs via fine scratches on the object or invisible cracks in the ground layer.

Fig. C9 is another experiment: Hinoki cypress is frequently used for the body of urushi ware and is slightly softer than maple wood.
beeswax test 2
Fig. C9   experiment on removing beeswax 2

Fig. C9d   One-third is plain wood and another part is treated with beeswax.
Fig. C9e   The beeswax on the bottom two-third was warmed till softened and scraped off with a spatula. Then cleaned with 96% alcohol, acetone, ethanol and petroleum ether. The bottom one-third was put in alcohol 'au bain-marie' of 75℃ for 15 minutes and cleaned with cotton cloth and warm alcohol. This part seemed to be free of any beeswax on the first hand.
Fig. C9f   After being lacquered with kijiro-urushi, the board was left to dry for one night. The bottom two-third of the board was brighter of colour than the plain upper part and seemed nearly dry.
Fig. C9g    The whole board was cleaned with petroleum ether. The upper one-third part had turned black, the urushi had dried completely, and there was no loss of the urushi layer after cleaning. Urushi on the middle one-third part was not fixed. The bottom one-third part which was washed with warm alcohol seemed to be pigmented slightly darker. Despite this the condition of the wood is not in a state that it will bear urushi or fillings and the surface is sure to erode in time

There may well be a more powerful cleaning method for the beeswax. But taking into account the condition of the old urushi object, the above-mentioned, warm alcohol method is already beyond the margin of safety and is not suitable in practice.

Fig. C10   before and
after restoring
This object dates from the end of Edo  period (mid-19th century). The areas where raden  tends to exfoliate are fixed with Japanese rice paper and wheat glue. Attachments such as hinges and keyhole accessory are removed with due care. Especially the joints had to be treated warily since they had been damaged heavily. On the construction of the framework, the hinges and the keyhole were initially not present, only later in Europe were they fitted on. 

Fig. C11   cleaning
Fig. C11   Firstly, the cleaning process is done. Animal glue was found in the exfoliating joint parts. Plaster in the gaps of the joints had to be scraped out with a knife. On the beak and a part of the bird's face, raden was missing and was painted with acrylic colours instead. Another missing part of the raden was filled with beeswax, but to avoid further loss of it, this part was to be cleaned later. Exfoliation of raden is fixed before the next phase.

kijomi-urushi absorption
Fig. C12   absorption of
Fig. C12   After cleaning the urushi layer had become brittle, needing absorption of diluted kijomi-urushi. For cleaning the left-overkijomi-urushi is wiped off thoroughly after absorption.
How you treat the object always depends on the condition of the object; it is a case by case approach. The object is dried in the furo for a few days. Urushiware that is kept and used in Europe, now and in the future, are to be inevitably exposed to a dry climate. Therefore in Europe, it is preferable to dry urushi in a furo with temperature and humidity that are lower than the Japanese standard. If it is given too much humidity in a short period of time, the object will deform and the exfoliation might even deteriorate.

fixing structure
Fig. C13   fixing joints
Fig. C13   The joint that was originally fixed with animal glue is bonded with animal glue.

whetting sabi layer
Fig. C14  whetting sabi
Gaps in the joints and the screw holes are filled with kokuso  and dried on room temperature. After hardening it is flattened. The surface of the kokuso  and small holes are filled with makiji  and sabi , following the line of the body . As these fillings are based on urushi, they reinforce the joints and edges.
Fig. C14   With synthetic whetstones and water the form of the ground layer is adjusted. Whetting is done only on the treated parts. Next, jisage  is done. Jisage  is the process of abrading the ground layer to create just enough space for the top layer. Diluted kijomi-urushi is rubbed onto the ground layer and wiped off carefully before drying in the furo.

removing beeswax
Fig. C15   removing
Fig. C15   Now the construction of the box is reinforced, the restoration of the raden  can be started. Any beeswax that is found in holes on the raden  is removed. The exfoliated part is fixed. Missing ground layer is filled. Once the filling has dried, a fine whetstone is used with water to lightly sand down the surface. After being dried, jisage  is done.

degreasing shell
Fig. C16  degreasing shell
Since the old raden has become thinner through aging, it is necessary to abrade the new shell on a flat fine whetstone with water.
Fig. C16   As raden the original kind is used. After abrading, the shell is degreased in a jar of petroleum ether overnight.

cutting shell
Fig. C17   cutting shell
The glueing surface is coated with animal glue two to three times and left to dry. Next, the glueing surface of the shell is coloured and lines are drawn following the existing design. Then it is steamed to soften the animal glue and put on the silver leaf.
Fig. C17   After the silver leaf has adhered, the shell is cut into form. The edges of the perforated shells are sanded if required.

fixing shell
Fig. C18   fixing shell
Fig. C18   Animal glue is put into the filling part and the shell is being fixed onto it with shimbari  sticks.

applying kiwa-sabi
Fig. C19   applying kiwa-
Fig. C19   Next kiwa-sabi  is applied. This sabi  is thinly applied around the inlayed raden  with a brush and cleaned with petroleum ether. Doing this sabi  remains in the grooves around the raden  which tend to exfoliate easily.

Fig. C20   applying urushi
Fig. C20   Urushi is applied to the ground layer of the joints, missing parts and other delicate areas. This is dried in the furo. Whetting with synthetic whetstone in due order. If sandpaper is used it must be finer than #2000.

Fig. C21   dozuri-polishing
Fig. C21   Next follows the dozuri-process, that smoothens the surface by polishing with dozuri-paste and a soft cotton cloth. This dozuri-paste is said to be of better quality when purchased on the market. In case of self-making, a mixture of elutriated whetstone powder and non-drying plant oil is used. In Japan colza oil is very popular, but in my experience pure olive oil is even better and there is no need to use expensive oil. After dozuri , the oil is wiped off completely with elutriated whetstone powder and petroleum ether.

Fig. C22   suri-urushi
Fig. C22   The last stage is that of applying the protection layers, suri-urushi. Dilute the kijomi-urushi and apply this onto the surface. Next, kijomi-urushi is wiped off thoroughly with soft tissues. As old objects are difficult to dry, especially the very first layer, this is left in the furo for 24 hours or longer. After the first layer the process of suri-urushi, wiping off and drying is repeated. With every layer the kijomi-urushi is thickened by reducing the amount of camphor, and the drying time shortens every time.

Fig. C23   tsuyaage-glossing
Fig. C23   When the last layer has dried the tsuyaage-glossing process can be started. There are good glossing pastes available on the market, although products with silicone deserve some caution. According to traditional technique, deer horn powder and non-drying plant oil as olive oil are used for glossing. It is important to let the deer horn powder absorb the oil completely, so that no oil remains after glossing. Using fine metal powder, as an alternative for deer horn powder is not ideal, since remaining metal powder could rust into small gaps or scratches.

protection cushions
Fig. C24   cushions and nest boxes
Fig. C24   Comparable examples like this box with aogaizaiku  originally contain seven nest boxes, while this one has only five. To prevent the nest boxes from moving around and cause damage to the bottom, special cushions are made. For further protection of the box a silk bag and an outer box are made in addition.

proceedings, 6th International Symposium Wood and Furniture Conservation proceedings, 6th International Symposium Wood and Furniture Conservation
Fig. C25   More detailed process is to be found in the following book: Sixth International Symposium on Wood and Furniture Conservation / The Meeting of East and West in the Furniture Trade ( Proceeding book: published by Stichting Ebenist, ISBN-90-806960-3-x)