PROBLEMS IN DIFFERENCE BETWEEN JAPANNING AND URUSHI 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. |
|
|
|
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.
|
|
|
|
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. |
|
|
|
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. |
|
|
|
Fig. C4 whetstones and knifes: (as clockwise from the left
top) charcoal / synthetic whetstones / knives / waterproof sandpaper |
|
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. |
|
|
|
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.
|
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.
|
|
|
|
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. |
 |
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. |
 |
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 |
|
AN EXAMPLE PROCESS OF TRADITIONAL RESTORATION
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. |
|
|
|
Fig. C12 absorption of kijomi-urushi |
|
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. |
|
|
|
Fig. C13 fixing joints |
|
Fig. C13 The joint that was originally fixed with animal glue is bonded with animal glue. |
|
|
|
Fig. C14 whetting sabi layer |
|
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. |
|
|
|
Fig. C15 removing beeswax |
|
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. |
|
|
|
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. |
|
|
|
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. |
|
|
|
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. |
|
|
|
Fig. C19 applying kiwa-sabi |
|
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. |
|
|
|
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. |
|
|
|
 
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)
|
|
HOME PROFILE GALLERY HISTORY URUSHI PROCESS DECORATION CONSERVATION LESSON
WORKSHOP EVENTS SHOP TREATMENTS RASH ! COPYRIGHT/REFERENCES 日本語ページ LINKS
Copyright / References / Contact
Copyright 2005 - 2008 urushi-kobo.com. All rights reserved. All images are protected by digital watermarking.
No reproduction or republication is allowed without written permission.
urushi-kobo.com, Amstelveen, The Netherlands
|
