| ■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 |
|
How the screens are being loaded
In the wake of a gas fumigation incident due to an erroneous agent in 2010, five Ekin Byōbu (folding screens painted by Ekin) 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 Ekin Byōbu‘ 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 Ekin Byōbu 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.
A FIT
installation of FIT
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.
Damaged Baird’s beaked whale specimen being X-rayed for investigation
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.
Packing for transportation
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.
Presentation of Hu Wei, Deputy Director of The National Art Museum of China
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.
Research on Asuka-daibutsu using a portable X-ray diffraction device
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.
During Lecture
Viewing of a video on research results
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.
Practical training on use of radiation measuring instrument
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.
Conservation of the Great Buddha of Kamakura, National Treasure
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.
A scene from the presentation
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.
Study Meeting on Records of Preservation Activities for Disaster-Affected Cultural Assets.
The “Study Meeting on Records of Preservation Activities for Disaster-Affected Cultural Assets.” was held on January 29, 2016. It was held as a part of the “research study for establishing the system of risk management and disaster prevention of cultural properties” now worked on by the National Research Institute for Cultural Properties, Tokyo under the promotion project of the National Taskforce for the Japanese Cultural Heritage Disaster Risk Mitigation Network implemented by the National Institutes for Cultural Heritage.
From the past till now, a large volume and a wide variety of recorded materials have been produced with regard to preservation activities for disaster-affected cultural assets, including on-site activity reports and meeting/communication records among concerned parties. These materials tell us problems they faced and provide us with clues for a perspective on future activities. With this in mind, the study meeting consisted of presentations on how the past records on preservation activities were kept and being utilized, followed by a discussion on potentiality of the activity logs.
The study meeting started with a report on collection and public release of materials that recorded an actual catastrophe (disaster-related materials), which was followed by reports based on a viewpoint of storage and use of activity records. Those reports were on activities of the Historical Records Network and the Committee for Salvaging Cultural Properties after the Great Hanshin-Awaji Earthquake, activities of preservation of local historical records and collection of materials relating to the evacuation centers following the Niigata-ken-Chuetsu Earthquake, and activities of the Japanese Council of Art Museums after the Great East Japan Earthquake. In the following session, there was an active discussion on how records are positioned in the preservation activities and how records of preservation activities are treated from the standpoint of the study of disaster-related materials.
In the field of preservation activities for disaster-affected cultural assets, not only the study from the aspects of techniques and systems but also continued discussion on the past activity records should be necessary. Through these activities, we hope to contribute to protection of historical culture against disasters.
Research Using Image Plate Developing Equipment
On November 10 through 12 following the first survey in August, we conducted an investigation into a pair of six-fold screens of “Birds and Flowers of the Four Seasons” (an important cultural property) at the Suntory Museum of Art. To investigate the production techniques and materials of the folding screens, we conducted research using an optical survey, fluorescent X-ray analysis, visible spectroscopy, X-ray radiography and other approaches.
As for X-ray radiography, we obtained X-ray transmission images with imaging plates. For this research, we brought the developing equipment, which is dedicated to imaging plates and were introduced to our institute in November, to the Suntory Museum of Art. Accordingly, at the site, we proceeded with the research by confirming the X-ray transmission images each time they were obtained. These images gave us a variety of information such as types and thicknesses of the coloring materials and production techniques.
We will summarize these research outcomes to publish a research report within FY 2015.
Dust removing & cleaning operations
Under the Cultural Properties Rescue Operations in Fukushima Prefecture of the Committee for Salvaging Cultural Properties Affected by the 2011 Earthquake off the Pacific Coast of Tohoku and Related Disasters, cultural properties t evacuated from the museums located in the former restricted areas of Futaba, Okuma and Tomioka Towns were tentatively stored in the school buildings of the former Soma Girls High School (Soma City). Excluding large or particularly heavy objects, almost all objects have been transported and stored in the temporary storage of the Shirakawa Branch of the Fukushima Cultural Property Center to be utilized for exhibition after dust removal, cleaning and recording. Due to longer-than-expected tentative storage, conservation environments in Soma City were examined again on October 15, 2015. After collecting the installed data loggers for temperature, humidity and illuminance, we measured the surface temperatures of the walls in the classrooms and insulation board applied on the windows for shielding. We also checked visual inspection of the objects for any damage incurred by insects and mold. Desiccant dehumidifiers installed in the classrooms where objects were stored had prevented the rooms from becoming highly humid even in the seasons with high relative humidity such as the rainy season and summer, maintaining their humidity at 50-60% rh in general from late February to mid-August. This means that the materials were not in a mold-active condition. We also found that the intensity of illumination was somewhat high and the temperature of the space up to 1 m away from the window was easily affected by the external environment. For those objects for which mold was a real possibility, we conducted cleaning operations. We will continually consider how to maintain better environments at the tentative storage sites based on our collected basic data.
The venue for a lecture at the forum
The scene of the satellite venue 1
The Center for Conservation Science and Restoration Techniques held the “IPM (Integrated Pest Management) Forum: 10 Years after the Abolition of Methyl Bromide Use: The Current Situation of IPM for Cultural Properties” on July 16, 2015. This event was jointly hosted by the Japan Society for the Conservation of Cultural Property, and was also held as a regular meeting of the society. This year marked the 10th anniversary of the abolition of methyl bromide use in and after 2005 decided by the Meeting of the Parties to the Montreal Protocol on Substances that Deplete the Ozone Layer. In this milestone year, we held the forum to review past activities, share information about the current IPM activities in the field of cultural properties, their progress and problems, and consider current challenges and the future direction. On the day of the forum, Mr. Takamasa Saito of the Cultural Affairs Agency, Ms. Rika Kigawa of the National Research Institute for Cultural Properties, Tokyo (NRICPT), and Mr. Sadatoshi Miura of the Bunkazai Chukingai Kenkyujo (research institute on insect and bacterial damage to cultural properties), respectively introduced fumigation techniques and subsequent IPM practices in Japan as well as countries around the world. In addition, various measures by individual museums were introduced from various perspectives by Ms. Mitsuko Honda of the Kyushu National Museum, Ms. Natsuko Nagaya of the Aichi Prefectural Museum of Art, Ms. Naoko Sonoda of the National Museum of Ethnology, Mr. Shingo Hidaka of the National Museum of Ethnology, Ms. Akiko Saito of the Natural History Museum and Institute, Chiba, and Ms. Mutsumi Aoki of the National Institute of Japanese Literature. Furthermore, Ms. Miyuki Asakawa of Ninna-ji temple introduced concrete examples of IPM activities in temples, while Mr. Yoshinori Sato of the NRICPT introduced an example of IPM practices at a conservation and exhibition facility for a decoratedtumulus, which is an environment for burial.
The forum was attended by 200 participants, and we set up two satellite venues at a meeting room (see photo 2) and a lobby in addition to the main venue at a basement seminar room of the NRICPT (see photo 1). In the lobby, we displayed copies of articles on IPM for cultural properties and measures against biological deterioration as well as related materials, and allowed participants to take them home for free. While it was regrettable that there was little time for discussion due to a series of heated presentations, we again appreciate that we could end the forum on a high note thanks to the cooperation from those concerned.
The training session in progress
This follow-up training session (the first for three years) was held on July 6, 2015, with the aim of helping to disseminate the latest knowledge in the field of materials conservation, aimed mainly at people who have already completed the “Training for Museum Curators in Charge of Conservation” training program; a total of 107 people attended the session.
With the coming into effect of the Minamata Convention on Mercury, under the terms of which restrictions will be imposed on the use of mercury and products containing mercury from 2020 onwards, production of certain types of fluorescent lamp will cease, and there will be a reduction in the quantity of incandescent light bulbs produced; as a result, switching over to the use of white LED lights for display lighting will no longer be optional and will in effect become “compulsory.” Following an overview of the Minamata Convention on Mercury (given by Chie Sano, Deputy Director of the Center for Conservation Science and Restoration Techniques), Naoto Yoshida outlined the current situation regarding the development of white LED lights. Kyoko Kubo of the Society for Preservation of Japanese Art Swords, Yusuke Kawase of the National Museum of Western Art, and Takako Yamaguchi of the Tokyo Metropolitan Museum of Photography were then invited to talk about the effectiveness of white LED lights as display lighting for Japanese swords, oil paintings and sculptures, and photographs, as well as the types of problems that have been experienced so far. Yamaguchi also discussed the impact that the Minamata Convention will have on daguerreotypes (a photographic technique that required the use of mercury).
There is still considerable uncertainty as to how things will develop in the future in regard to the production of the fluorescent lamps and halogen lamps that have been used up until the present to provide the extremely high color rendering performance needed for display lighting; more work needs to be done in this area in terms of the collection and presentation of relevant information. It was also made clear from the talks given at the training session that there is a real need for clarification, from a natural sciences perspective, of the reasons why objects look different when viewed under LED light (compared to how they appear when viewed under conventional lighting), despite the fact that, statistically speaking, LED lights should in theory possess adequate color rendering performance.
Cultural property pest identification hands-on training in progress
The “Training for Museum Curators in Charge of Conservation” training program has been held every year since 1984, with the aim of imparting basic know-how and skills to curators responsible for conservation work. This year’s training program was held over a two-week period starting on July 13, 2015, with 32 participants from all over Japan.
The curriculum for this year’s training program focused on two key areas: facility environmental management (including temperature and humidity, air circulation, and prevention of biological damage, etc.), and the factors behind, and forms taken by, deterioration of different types of materials. Experts from the Institute’s staff, as well as external experts, gave lectures and led practical, hands-on training sessions. The Museum of the Sakitama Ancient Burial Mounds (in Saitama Prefecture) kindly made available its facilities for the implementation of a hands-on museum environment survey case study, in which the training program participants were divided into teams of eight trainees each to undertake surveys focusing on different themes; the trainees subsequently gave presentations on the results obtained in these surveys.
This year marked the 32nd year that the “Training for Museum Curators in Charge of Conservation” training program had been held; a whole new generation of curators is now receiving training. Today, many of Japan’s public museums in particular have reached an age when they need to undergo renovation or renewal of their facilities; the Institute will be working to strengthen the provision of this type of training program in the future, with the aim of ensuring that know-how relating to both the theory and practical methods of materials conservation can be handed down to a new generation of curators.
Joint research regarding the structural reinforcement of stone pagodas (Seven-storey stone pagoda at Myodo-ji Temple)
Following the concluding of a memorandum of understanding (MoU) between the Center for Conservation Science and Restoration Techniques and the Conservation Science Division, National Research Institute of Cultural Heritage, Republic of Korea, the two organizations have been collaborating on “Joint Research between Japan and Korea—Research on the Effect of Environmental Pollution on Cultural Properties and Development of Conservation Techniques.” More specifically, they have been undertaking joint field studies of cultural properties made of stone in outdoor locations in both countries, and have been holding annual research results presentation sessions, with the venue alternating between Japan and Korea, with the aim of sharing the research results achieved in each country.
This year’s research results presentation was held in Japan on July 8, 2015, in the Basement Level Meeting Room of the National Research Institute for Cultural Properties, Tokyo. The theme for the presentation was issues relating to the structure of stone-built cultural properties. The Japanese and Korean researchers reported on and discussed their respective research results. In addition, taking advantage of the Korean researchers’ visit to Japan for the presentation, a study visit was arranged to examine the nine-storey stone pagoda and seven-storey stone pagoda, etc. at the Myodo-ji Temple in Yunoma Town, Kumamoto Prefecture (where the Japan-based joint field studies have been undertaken), and to exchange information regarding new developments in structural reinforcement methods.
Demonstration of Microfading device
On June 4, 2015, Dr.Paul Whitmore, professor at Yale University (the U.S.) and director of the Institute for the Preservation of Cultural Heritage, visited the National Research Institute for Cultural Properties, Tokyo, and conducted a demonstration of Microfading, the state-of-the-art spectroscope capable of measuring color deterioration in a microscopic region. Microfading is a most-advanced technology that has not been introduced in Japan yet, and Mr. Whitmore introduced the purpose and structure of the device as well as its application cases in the United States to researchers of the Center for Conservation Science and Restoration Techniques as well as teachers and postgraduates of Tokyo University of the Arts. According to Mr. Whitmore, the method of grasping changes in color fading with the passage of time by exposing an object through fiber to the high-intensity light of a xenon lamp with an aperture width setting of 0.3 millimeters is used to determine which color is vulnerable to light exposure among actual exhibits. The idea of the method is opposite to that of the conventional one that limits the exposed time by identifying an object and then judging its light resistance. While there are only a few application cases of Microfading, I felt that the technology has the potential to expand possibilities for the future. Concerning dyed textiles made at the institute (red: carminic acid, yellow: curcumin and blue: indigo), we conducted a color fading experiment to create a final color-difference level of 33, but we could not find discolored spots both visually and by using a stereomicroscope. (Of the attendees, eight were from outside institutions.)
We held a workshop on “the Minamata Convention on Mercury” at the Tokyo National Museum Lecture Room on June 9, 2015. The Convention stipulates comprehensive regulations to reduce the risks of mercury on human health and the environment, and was adopted and signed on October 10, 2013, at a diplomatic conference held in Kumamoto Prefecture. It includes limitations on the use of mercury as well as a ban on the manufacturing, import or export of mercury-added products, also having effects on cultural property conservation. Thus we discussed the contents of the Minamata Convention on Mercury and its impact with representatives from collaborative partners of the Center for Conservation Science and Restoration Techniques having a large variety of expertise, such as the Tokyo National Museum, the Kyoto National Museum, the Nara National Museum and the Nara National Research Institute for Cultural Properties, as well as Cultural Affairs Agency officials in charge of the matter and representatives from the agency’s fine arts division.
As for cultural property materials and techniques using mercury, we agreed to carefully monitor the future direction of regulations in order to reduce negative effects as much as possible on the restoration and replication of cultural properties such as cinnabar as an electroplating technique or a drawing material and the replication of Daguerreotype pictures. In addition, we also agreed to act to express opinions when necessary. Meanwhile, before the production of mercury lamps and fluorescent lamps is discontinued, we decided to exchange views on the use of LED lights and its beam quality evaluation. In the workshop, we could shed light on problems from various perspectives such as a natural history sample, academic sample and modern industrial devices using mercury and the disposal of waste soil at excavation sites, and we realized the very wide range of expertise.
The investigation conducted at the Izu-no-Chohachi Art Museum
For research on materials and structures of cultural properties, non-destructive and non-contact methods are required frequently. Therefore, investigation techniques using X-ray play an important part. With X-ray radiography, one of the techniques using X-ray, it is possible to investigate the inner structure and the layer of materials, both of which cannot be visually confirmed, in a non-destructive and non-contact way by using the difference in X-ray transmission levels resulting from a difference in density and thickness of the material composing cultural properties.
The latest research was conducted on works of Chohachi Izu, a kote-e (plaster relief) artist who was active from the late Edo period to the early Meiji era. Chohachi left a large number of statues and kote-e works – paintings drawn with plaster using a trowel, a tool used by plasterers to plastera wall. To investigate the techniques for producing these works, we conducted an investigation into the inner structures of these works using X-ray radiography on the second floor of the Izu-no-Chohachi Art Museum in the town of Matsuzaki, Kamo-gun District, Shizuoka Prefecture, on May 19 and 20, 2015. As a result of our research, we identified the layered structure of a kote-e work sets in frames, the inner structure of statues and their production techniques.
