This seminar has been conducted since 1984 in order to convey basic knowledge and techniques to curators working on the conservation of materials at the cultural property conservation facilities. For 2017, the two-week seminar starting from July 10 attracted 31 participants throughout Japan. The curriculum of this seminar consists of two major topics: management of the facility environment such as temperature and humidity, air quality, and prevention of pest damages; factors and manners of deterioration according to material types, as well as its prevention. Experts inside and outside the Institute gave lectures and practical training. For the “Case Study,” where the participants experienced the museum environment research on site, they visited Saitama Prefectural Museum of History and Folklore. After dividing into eight groups, they implemented research under the theme set by each group, and presented the outcomes at a later date. Under the current circumstances whereby many facilities are planning large-scale renovation and major movements related to the conservation of materials, such as shifting to LED lighting, are under way, we will scrutinize the curriculum further for smooth technical transfer of proper management.
|■Tokyo National Research Institute for Cultural Properties||■Center for Conservation Science|
|■Department of Art Research, Archives and Information Systems||■Japan Center for International Cooperation in Conservation|
|■Department of Intangible Cultural Heritage|
On August 19th (Saturday) to August 27th (Sunday), the Modern Cultural Properties Section of the Center for Conservation Science conducted a survey on the conservation and restoration situation of iron structures built in the Japan colonial period (1895-1945) existing in Taiwan. In this survey, we focused on a large-scale factory and iron bridges. The preservation of Japanese colonial buildings began in earnest following the end of martial law in 1987, and about half of all Designated or Registered Cultural Properties are Japanese colonial-era buildings. For this survey, although we focused on a sugar-refining plant, since tobacco and brewed liquor factories had a monopoly on the country until the 1990s, many of their factories and machinery have been left untouched. Although these factories are greatly influenced by their location, many factories in large cities such as Taipei have been assigned new roles by town planners, and are used as commercial and cultural facilities. On the 22nd, we visited the Bureau of Cultural Heritage, Ministry of Culture, and held a discussion with Director-general Gwo-Long Shy on the efforts to preserve Taiwan’s cultural assets. Since 2000, Taiwan has made efforts to preserve its industrial system of production, distribution and manufacturing. This has led to an active exchange of ideas regarding renewed interest in the preservation of Japan’s own industrial heritage.
To conserve Japanese paintings, calligraphic works and other pictorial artifacts, we are now increasingly required to have some knowledge of conservation science. To meet these demands of conservators who wish to learn how to handle chemicals, particularly those that have recently become more popular in restoration sites, and how to apply them in conservation and restoration works, the Tokyo National Research Institute for Cultural Properties and the Association for Conservation of National Treasures (ACNT) jointly conducted a workshop with training program for conservators from August 8 to 9, 2017, which included lectures on basic knowledge and practical work sessions. The workshop aimed to provide hands-on knowledge that can be applied to actual conservation works. To achieve this purpose, we designed a curriculum that would help participants accurately understand the chemical property of organic solvents and enzymes as well as the proper handling of basic laboratory instruments and chemicals for more effective and safer restorations.
A total of 11 people, one from each corporate member of ACNT, participated in the workshop. Dr. Sano, Director of the Center for Conservation Science; Dr. Sato, Head of the Biological Science Section; and I provided lectures on the safe handling of organic solvents; integrated pest management (IPM) for cultural properties at restoration studios; and removal methods of adhesives and stains, respectively. Based on these lectures, the participants practiced removing various types of stains on the sheets of paper that we prepared, by using suitable solvents and enzymes. The practical work session also covered other topics such as the use of cyclododecane as a temporary protective coating for water-sensitive colorants. Mr. Kimishima, ACNT’s Senior Conservator, taught in the work session and provided hands-on training to the participants.
The program ended with a lively Q&A session and discussion. We will continue to hold such workshop in the future.
Many thousands of cultural properties were severely damaged by the tsunami that occurred following the 2011 Off the Pacific Coast of Tohoku Earthquake. Although six years have passed from the disaster, treatment of the tsunami-damaged cultural properties continues in the disaster-stricken areas. In order to investigate the occurrence of volatile organic compounds, which are harmful to workers’ health, we made a contract with Rikuzentakata City and conducted a survey on the treatment methods for the tsunami-damaged cultural properties and on the working environment in the facility where treatments are conducted.
We visited the treatment facility in the Rikuzentakata City Museum, which is located in a temporarily closed school facility in Iwate Prefecture, for on-site research in August from the 25th to 26th. Damaged folk cultural properties are bathed in water for desalination in the school yard. On the first floor, paper documents are treated for desalination in a teachers’ room and cleaned natural history specimens are classified in a classroom. Treated objects are stored separately according to each type of cultural property in the classrooms on the second floor or a temporary installed storage facility in the gymnasium.
We were able to obtain a lot of valuable data about the air quality in the facility and water quality during treatment, helped by the cooperation of the museum staff. Temperature and humidity in the facility are continuously measured even now. By the end of this fiscal year, we plan to propose improvements after collecting data.
We conducted an optical study of the Ryukyu paintings at Okinawa Prefectural Museum & Art Museum on June 20-23, 2017. In order to investigate the depiction techniques and coloring materials, high-resolution color imaging and X-ray fluorescence spectrometry were applied for ten paintings held by the Okinawa Prefectural Museums and the Okinawa Churashima Foundation. Ryukyu-koku no zu, an important cultural property, held in Okinawa Prefectural Library was also investigated.
Many of the Ryukyu paintings have disappeared due to the warfare of World War II, and sufficient research has not been performed. We have conducted optical studies of the Ryukyu paintings located inside and outside Okinawa Prefecture since 2008. Optical study of the Ryukyu paintings will continue to be conducted in the future and the results will be published. We believe that the study is of great help in deepening the understanding of the Ryukyu paintings.
A fault exposed in a paddy field due to the 2016 Kumamoto Earthquakes attracted much attention, calling for the necessity of its preservation (as a result, it is designated as a natural monument by Mashiki Town today). As a good example of disclosing and utilizing such preserved fault exposure, the Nojima Fault Preservation Museum (where the fault exposed due to the Hyogoken-Nanbu Earthquake, which triggered the Great Hanshin-Awaji Earthquake, is preserved) established in 1998 is well-known in Japan. In 1999, the Jiji Earthquake occurred in Taiwan. We visited a museum constructed following the Nojima Fault Preservation Museum with further development near Taichung, the damage of which was specifically serious. The 921 Earthquake Museum of Taiwan works well as a disaster prevention museum, which shows earthquakes with a focus on the effectiveness of quake resistance and quake-freeness by conserving a damaged junior high school building with a shelter constructed as the exterior walls of the museum for disclosure. On the other hand, the Chelungpu Fault Preservation Park is a scientific museum, where an exposed fault section confirmed during the survey is directly exhibited inside the housing. The museum also shows the mechanism of an earthquake and the history of past quakes. Particularly, by means of project mapping focusing on the fault surface, they visually show the history of complicated strata in sequence, which is difficult to understand from the current plane of stratification. Application of such an approach is expected in various fields also in Japan, including explanations about remains at archeological sites besides the exhibition of the strata.
The Center for Conservation Science has studied restoration materials for cultural properties.
The great Torii of Itsukushima Shrine is located on the coast. Since it is exposed to the wind, the rain and the waves, we have to select restoration materials with high weathering performance, which can also save restoration time.
Based on the above, we studied which fillers and surface-finishing agents were the most suitable for use in the great Torii from 2010 to 2016. After a small pillar of the great Torii was partially restored last year, we researched it on May 25.
We are going to observe the progress and cooperate with conservators for restoration planning.
We have been conducting a joint project with the Iwate Prefectural Museum to determine the methods to stabilize the paper materials damaged by the tsunami in the City of Rikuzentakata, Iwate. In Iwate Prefecture, many documents and other paper materials were damaged by the tsunami that hit the area in 2011. We have already stabilized approximately 90,000 paper materials, but it is still unclear when we will be able to complete the work of stabilizing all the damaged materials. The joint study conducted up to last fiscal year has enabled us to estimate almost all causes of the odors emitted from the paper materials. In this fiscal year, therefore, we have been working on establishing the methods to eliminate the odors from the stabilized materials, and also on a plan to keep records of the stabilization processes to determine how to improve them and what conditions cause paper materials to develop odors. On May 17, we visited the Iwate Prefectural Museum to discuss plans for this fiscal year as well as to install some equipment, together with our co-investigator, Mr. Hideo AKANUMA, in the conservation and restoration laboratory for tsunami-damaged cultural properties of the Rikuzentakata City Museum, which is located next to the Iwate Prefectural Museum. In this laboratory, we tentatively installed the equipment to monitor water temperature and oxygen concentration levels, and also installed surface temperature/humidity measuring equipment to check the temperature and humidity of the laboratory as well as to identify the transfer of temperature inside it. We plan to conduct joint investigations in June and July, each for a period of approximately one week.
Structures of historical buildings in Iran are mainly made of bricks or clay walls. However, wood is also used for making its roof frame, beams, window frames and so on. Damage of termites is found extensively in the central to southeastern parts of Iran, including Isfahan according to a preliminary survey conducted last fiscal year, and it is the major issue of the conservation of historical buildings in these regions. Termites are notorious as an insect pest for wooden materials. Their damage used to be widely found in Japan as well, but preventive measures have been gradually established to date. In order to support for establishing appropriate measures for conserving wooden built heritage and historical objects in Iran by sharing such knowledge, Tokyo National Research Institute for Cultural Properties (TNRICP) and Iranian Cultural Heritage, Handicrafts and Tourism Organization (ICHHTO) co-organized a workshop on insect damage to wooden cultural properties in Isfahan from April 17th through 19th, 2017.
From Japan, Mr. Masahiko TOMODA and Mr. Hiroki YAMADA of the Japan Center for International Cooperation in Conservation of TNRICP, Mr. Yukio KOMINE of the Center for Conservation Science of TNRICP and Mr. Kazushi KAWAGOE, Senior Researcher of Institute for Environmental Culture, participated in the workshop. From Iran, more than 20 experts got together from various parts of the nation, including Yazd, Tehran and Gilan, as well as Isfahan. On Day 1 and Day 3, presentations were given from both sides on materials and structures of historical buildings in both countries, and actual cases and monitoring surveys of insect pest damage to them. On Day 2, to discuss specific measures and others, all participants visited historical buildings to conduct a survey to identify termite damage and a test to install IGRs (Insect Growth Regulators) that does not affect the environment badly.
We heard that after the workshop, ICHHTO began preparation for establishing a new laboratory engaged in research on the prevention of termites in Isfahan. We believe that this workshop was able to contribute to conserving Iran’s valuable cultural heritage in any way.
The 『Report of the Optical Study for the Ryukyu Paintings』was published by the Tokyo National Research Institute for Cultural Properties in March 2017. The Ryukyu paintings refer to paintings drawn in the Ryukyu islands during the Ryukyu dynasty era, although they have not been definitively defined. The paintings were largely influenced by Chinese and Japanese paintings, but the depiction and coloring are different from those paintings. Many of the Ryukyu paintings disappeared during World War II, and sufficient research has not been performed.
We have conducted an optical study of the Ryukyu paintings located inside and outside Okinawa Prefecture since 2008. In this report, high-resolution color images and the results of coloring materials by X-ray fluorescence spectrometry were analyzed for eleven paintings held by the Okinawa Prefectural Museums and the Okinawa Churashima Foundation.. It is the first time that an optical study of Ryukyu paintings has been conducted, and we believe that publishing the results of the study is of great help in deepening the understanding of the Ryukyu paintings. We hope that this report will be widely used for research on the painting and art history of Japan. Although this report is not for sale, it can be viewed at prefectural libraries throughout the country.
In the wake of a gas fumigation incident due to an erroneous agent in 2010, five gold picture screens became discolored. Based on the method that was determined as a result of discussing a policy for addressing the issue among parties concerned, including the Tokyo National Research Institute for Cultural Properties (TNRICP), these gold picture screens’ surface had been stabilized since 2012. They were finally returned to the Ekingura (Konan City, Kochi Prefecture) on April 17th, 2017 (carried out of the TNRICP on April 14th). With the screens’ safety as top priority, as a treatment to stabilize the surface, the following measures were taken: 1) The screens were dismantled to perform cleaning to remove the agent on the paper; 2) Prevention of the exfoliation of a paint layer, repairing of the paper, mending of a rupture of the paper, replacement of the lining paper and retouching of the repaired places; and 3) replacements of the foundation, osoigi frame support, karakami lining paper and metallic materials and reconstruction into a 2-panel folding screen. Each screen was packaged in order of a gas barrier bag, a screen bag and a cardboard box and delivered by a land vehicle specifically designed to transport art objects.
In the presence of the Kumamoto Art and Culture Promotion Foundation, to which they were returned, the five screens were stored in a treasure house safely and the Ekingura Management Committee, the Akaoka Gold Picture Screen Preservation Association and those parties concerned in Kochi Prefecture and Konan City appeared to be pleased. Though it was unfortunately rainy, when the truck arrived and the screens were carried in, it stopped raining as if the parties’ wishes came true. The TNRICP will give advice on a preservation environment for the gold picture screens from this point onward.
Basic Research Underway for Developing New Ways of Killing Insect Pests in Historical Wooden Architecture (How to Capture Insect Pests)
The Center for Conservation Science has been moving forward the basic research on “hot-air processing” as one of the new ways of exterminating insect pests in historical wooden architecture. It heats a structure while maintaining a steady moisture content so that wood or coloration sustains no damage, thereby exterminating insect pests that perforate members inside the building, such as columns and beams, or cause feeding damage to them.
In research such as this, it is ideal to use insect pests that actually cause damage when evaluating insecticidal effects. However, it becomes necessary to identify ways of collecting living insect pests efficiently or to establish an artificial rearing method to ensure their steady availability. To that end, we here discuss ways of capturing them.
In the case of ordinary sticky traps for capturing flying insects, because an adhesive substance adheres to the insect pests captured, it is difficult to catch them alive. We therefore looked into how they are captured by applying a method called a Flight Interception Trap (FIT). The FIT utilizes the characteristic that a flying insect shrinks its wings or legs and falls when hitting an obstacle and thus is made up of a transparent collision plate and a trapping container installed underneath.
When we conducted a survey on insect pests captured by using a FIT at a temple on Mt. Nikko this fiscal year, we succeeded in capturing the intended insect pests (mainly deathwatch beetles) alive. Being able to capture them alive can not only provide clues to elucidating their biology or life history but also lead to artificial rearing.
We believe that it is important to accumulate the results of such basic research activities as the foundation underpinning the development of new ways to exterminate insect pests in historical wooden architecture.
The Baird’s beaked whale specimen (Berardius bairdii : nickname “Tsutchy”) exhibited at the Rikuzentakata Sea and Shell Museum is a whale (total length is about 10m) that was stuffed to celebrate the meeting of the International Whaling Commission in Tokyo in 1954. The specimen was damaged by the great east Japan earthquake and tsunami on March 11th, 2011. After the primary inspection of damage at the museum on May 28th, 2011, the specimen was transferred to the Tsukuba Research Department of the National Museum of Nature and Science on June 30th, 2011. Currently, the project for restoration of the specimen is in progress.
In this project, it is important to understand the structure of the timberworks and the location of corroded nails inside the specimen. At the request of the National Museum of Nature and Science, Masahide INUZUKA and Midori HAMADA investigated the inner structure of the specimen using X-ray radiography from October 16th to 18th and from 23rd to 25th, 2016. For this research, we used the developing equipment, which is dedicated to imaging plates that were introduced to our institute in 2015. Accordingly, we proceeded with the research by confirming the X-ray transmission images each time they were obtained.
To investigate the overall inner structure of the specimen with the total length of about 10m, we obtained 375 X-ray images in total. The information about the structure of the timberworks and the location of corroded nails inside the specimen obtained from these X-ray images will be referred to during the investigation using an endoscope and the restoration works.
The Tokyo National Research Institute for Cultural Properties (Tobunken) has been conducting the project “Work on the investigation of the preservation measures for Kitora Tumulus, a special historic site” since 2004. As the mural paintings in the tumulus required conservation treatments, it was decided that they would be removed from the tumulus and currently conserved externally. Three types of conservation treatments were conducted: maintaining the mural paintings in the tumulus, removing the mural paintings from the tumulus stone, and reconstructing the mural painting fragments. The removal of the mural paintings had been conducted for over 6 years, and the paintings were separated into 1143 fragments. The paintings have been reconstructed in the restoration facility in Asuka-mura, Nara prefecture. The Tobunken team has developed conservation techniques and performed experimental checks for this project, and the Association for the Conservation of National Treasures, an association of conservators for Japanese paintings, has applied the developed techniques.
On August 24th and 25th, 2016, three reconstructed mural paintings, the south wall with suzaku, west wall with byakko, and the ceiling with an astronomical chart were moved from the restoration facility to “Shijin no yakata”. This museum opened on September 24th, and the three mural paintings was exhibited for a month.
Dr. Yasuhiro Hayakawa (Center for Conservation Science) attended the International Symposium on the National Art Collection’s Conservation held in the National Art Museum of China, Beijing. The National Art Museum of China is the largest art museum in China and established the conservation center a few years ago. The art museum has been promoting the conservation of art works in the conservation center and has completed communication and cooperation with foreign conservation institutions.
Fourteen researchers and restorers in the field of conservation and restoration were invited from Japan, US, UK, Italy, Germany, Hong Kong and Taiwan. Nineteen talks on topics such as the philosophy of conservation, examples of paintings’ conservation and results of scientific investigation were presented in the symposium. Dr. Hayakawa presented the research work of the material analysis of the Japanese paintings using cutting-edge technology. More than 30 directors of public art museums in China also participated. It shows that China is actively promoting the establishment of philosophy and the acquisition of conservation for artworks.
In Asuka-dera Temple located in Asuka village, Nara prefecture, the statue of Shaka Nyorai (the so called “Asuka-daibutsu”), which is about three meters in height, is enshrined as the principal image of the temple. According to historical sources, the statue is considered to have been made by Tori Busshi in 606. It is an important statue because it is considered to be the first Joroku Buddha in Japan. However, there are various opinions as to which part of the statue was originally made by Tori Busshi because it was damaged by fire in the early Kamakura period.
After the opening time of Asuka-dera Temple on June 16th and 17th in 2016, research on the preserved state and production techniques of Asuka-daibutsu was conducted by experts in art history, conservation science, restoration and three-dimensional measurement. This research was managed as a part of the “Japan-South Korea Joint Research on Bronze Buddhist Statues of East Asia from the 5th through the 9th Century” (the research representative is Prof. Fujioka of Osaka University.). From the National Research Institute for Cultural Properties, Tokyo (NRICPT), Yasuhiro HAYAKAWA, Masahide INUZUKA and Mai SARAI participated in this research and conducted the investigation of materials on the surface of the statue by using a portable X-ray diffraction device (RIKEN KEIKI Co., Ltd., XRDF), which was introduced to NRICPT in the last fiscal year.
Scaffolding was constructed around the statue, and then we carried out the measurement on the surface of the head and body of the statue (the number of measured points was 10). Together with the 3 measured points on a fragment considered to have been a part of Asuka-daibutsu, the number of measured points was 13 in total during this research period.
The crystal structure of materials can be obtained by the portable X-ray diffraction device. The chemical compounds can be identified from the information about the crystal structure by combining the information about the elements constituting materials obtained by X-ray fluorescent analysis conducted by Osaka University and the National Museum of Korea. In this research, copper compounds existing on the surface of the statue can be identified and the comparison of chemical compounds on different measurement points will be possible.
We are now analyzing these data in more detail, and plan to report the results of the analysis within this fiscal year.
Under the project of “Study on the storage environment for cultural properties,” as one of the major topics, a research has been conducted regarding purification of air inside the display case with high concentration of pollutant gases, which might cause damages on the cultural properties. Conference on Conditions for Conservation of Cultural Properties was held on February 15th, 2016, under the subtitle of the “Evaluation of the Concentration Measurement and Air Cleaning Technology Using a Full-Size Display Case for Experimental Use.”
In this conference, based on the tentative plan for the outgas test method that was made for appropriate selection of interior materials and the results of data collection/analysis of outgas of the interior finishing materials, reports were presented on measurement of outgas concentration, visualization of airflow, the test for air cleaning function inside the full-size display case, as well as actual examples to address pollutant gases at museums.
The problem of generation and retention of gas inside the airtight case is being widely recognized and a total of 135 participants, including curators, attended the meeting from various parts of the country. At the Q&A session, many questions were raised concerning countermeasures, etc. that should be required for actual display cases. Although this issue will not be included in the next mid-to-long term project, we are planning to produce and publish a “pollutant gas management manual” within the next fiscal year for use of museums.
Two workshops titled above were held, including the 1st workshop at the Minami Soma City Museum on November 4th, 2015 and the 2nd workshop at the Shirakawa Branch of the Fukushima Cultural Property Center on January 28th, 2016. The workshops included lessons on basic knowledge of radial ray, practical training of how to measure radioactivity, and experience of dust removal. As for the 1st workshop that was the first of its kind held in Hamadori, the people seemed to have been looking forward to getting skill concerning the radiation accident and participated in the workshop in an enthusiastic manner. A practical training on how to deal with plants was also included by using botanical specimen in drying as teaching material. In the training, it was explained that radiation dose rate was higher in soil attached to the roots than in the leaves. Further, as it was found that there was a delay in delivering information regarding how to deal with materials damaged by the tsunami disaster that had been discussed in Tokyo in May 2011, the methods of the squelch-drying technique were offered (30 participants). As for the 2nd workshop, how to deal with materials damaged by water disasters that might possibly occur in the future was added to the training programs (17 participants). In nearly 5 years since the disaster on March 11th, 2011, the radiation dose rate in Fukushima has dropped except in some areas and the people who had worked on rescue of cultural properties in Fukushima at that time were subsequently replaced by younger generations. Aiming to prevent deterioration in disaster-prevention awareness and the related skills, we would like to continue holding the workshop every year and support people who work on excavation of Hamadori where post-disaster reconstruction is delayed and who work on rescue of cultural properties there.
The National Research Institute for Cultural Properties, Tokyo was entrusted with conservation work of the great Buddha of Kamakura in Kotoku-in temple. In this work, for the first time in 55 years after the major conservation in 1959, the noble statue is enclosed by the scaffolding in order to perform recording the present condition, cleaning, metal analysis, climatic investigation, microtremor measurement, investigation of the seismic isolator, and high-resolution image photographing. With regard to the Great Buddha of Kamakura, the National Research Institute for Cultural Properties, Tokyo was also involved in gamma-rays transmission photographing that was implemented during the major conservation in 1950s, and the sampling analysis relating to copper corrosion as well as the environmental research that were implemented in 1995. In this work, it was scheduled that the surface rust was analyzed for the first time by means of the non-destructive analysis method such as XRF (X-Ray Fluorescence analysis) and XRD (X-Ray Diffraction analysis) and further detailed damage record was taken, based on which we expect to accurately know details of the current preservation state. The scheduled work also included checking of the condition of the sliding base isolator that was installed as earthquake countermeasures at the time of the major conservation in 1959.
The 29th Study Meeting on the Conservation and Restoration of Modern Cultural Properties
“Conservation and Restoration Philosophies for Modern Cultural Properties”
On January 15th (Friday), the Modern Cultural Properties Section of the Center for Conservation Science and Restoration Techniques held a study meeting titled “Conservation and Restoration Philosophies for Modern Cultural Properties” at the Institute’s seminar room. The study meeting was featured by four guest speakers: Mr.Rorf Hoehmann (Owner and Head of Office of Industrial Archaeology), Dr. ITOH Takashi (Chairman of the Japan Industrial Archaeology Society), Dr. KIMURA Tsutomu (Professor, Nagaoka Institute of Design), and Dr. SUZUKI Jun (Professor, The University of Tokyo). Mr.Hoehmann made a presentation on the conservation and restoration philosophies for industrial heritage in Germany. Dr.ITOH spoke on the conservation and restoration philosophies for each of three categories of the modern cultural properties that included Architectural Heritage, Civil Engineering Heritage, and Industrial Heritage. Prof. KIMURA made a presentation on the current situations and problems of modern cultural properties that are observed through the efforts in conservation and restoration of modern western-style buildings. Prof. SUZUKI, in view of his expertise in industrial technology history, told about the necessity of conservation of heritage, because we can find the history of technology from such heritage. The lectures were all very convincing as they were based on practice, to which the audience listened in an enthusiastic manner. As many participants indicated in their responses to the questionnaire conducted after the meeting, we also feel it important to further deepen discussion on the issue of conservation and restoration philosophies not on an ad hoc basis but on a continuous basis. Aiming to contribute to deepening discussion, we will make further efforts to promote our research study.