The Surging News reporter Gao Dan sorted out
Following the third season of CCTV's "National Treasures" this year, it entered the Forest of Steles in Xi'an to introduce cultural relics such as "Kaicheng Stone Classic" and "Zhaoling Liujun". The past of Zhaoling Liujun was recalled. The Surging News learned that the "Record of the Restoration of the "Two Juns" of Zhaoling" published by the Shaanxi People's Fine Arts Publishing House recorded in detail the past of the "Six Juns of Zhaoling" and the reasons and experiences of the restoration of the "Two Juns".
The Zhaoling "Erjun" (Fist Hair and Salu Zi) has not been protected or restored since it officially entered the Museum of the University of Pennsylvania in 1920. From the theft of the Zhaoling Tomb in 1912 to the restoration of the Museum of the University of Pennsylvania in 2010, a full 98 years have passed.
Zhou Ping, the author of "Zhaoling "Erjun" Restoration Record", is one of the three experts who stood out from many stone cultural relics restoration experts in 2010 and went to the United States to restore "Erjun", which is also the first time that China sent cultural relics experts abroad to participate in the restoration of Lost Chinese cultural relics.
The highest attainment and the most well-known ancient horse modeling art in China is the "Zhaoling Liujun". The "Zhaoling Liujun" stone carvings are based on the mounts that Emperor Taizong li Shimin of Tang Dynasty rode in the five years from 618 to 622 AD, and they were the mounts he rode to assist his father Li Yuan of Tang Gaozu in pacifying the four seas, establishing a state, and consolidating the new regime of the Tang Dynasty.
In the tenth year of Tang Zhenguan, Li Shimin ordered the great painter Yan Liben to first paint the figures of liujun, and then the stone carver Yan Lide presided over the carving according to the shape of the painting. Li Shimin personally composed six poems (i.e., "Six Horse Praises"), praising the style of each horse, and ordered the great calligrapher Ouyang Qing to copy them down, and then Yin Zhongrong carved them next to the "Six Juns", which is called the "Five Absolutes", so they represent the highest level of stone carvings in tang tombs. "Zhaoling Liujun" adopts high relief techniques, with simple lines, accurate shapes, vividly showing the posture, personality and scene of the war horse galloping on the battlefield, and each picture tells people a thrilling historical story.
Former site of Zhaoling Liujun
The story of "Zhaoling Liujun" is full of ups and downs, in addition to the hehe at the time of creation, their fate in later generations is also very bumpy, the "Zhaoling Liujun", which was originally built on the zhaoling tomb of Li Shimin of Tang Taizong and Empress Wende's changsun clan, is now four pieces hidden in the Forest of Steles Museum in Xi'an, and the other two pieces, "Salu Zi" and "Fist Hair" are collected in a university museum in Pennsylvania.
The story of "Erjun" begins with the famous collector Lu Qinzhai, the owner of the Laiyuan Company in New York, who was a famous international cultural relics dealer and a great antique dealer in the early 20th century. According to Lu Qinzhai in his memoirs, "Erjun" was smuggled from Zhaoling in 1912. Later, with the assistance of Yuan Shikai, it was transported to the United States. After that, the "Second Horse" came to the University of Pennsylvania and became the two pillars of its museum. Many museum enthusiasts come to Penn just to see the original "Erjun", especially the "SaluZi", the only horse with a human figure among the six juns.
The exiled "Erjun" has never been forgotten, and after it was collected by the Penn Museum in 1918, it has always been the object of key protection, covered with plexiglass protective covers, placed in important protected areas... But after all, more than 90 years have passed, coupled with the fact that when the "Erjun" was transported to the United States, it was spliced together by pieces, "Erjun" is a bit "worthy of the heavy load", in order to go out to the needs of the exhibition, in 2010, the Penn Museum decided to start the restoration work, and invited the Shaanxi Tang Daming Palace Cultural Relics Conservation Foundation to send two or three Chinese cultural relics experts to the United States to assist in the restoration, so that the "Erjun" can safely go to the outside world for exhibition in the future.
At the beginning of 2021, the third season of CCTV's "National Treasure" entered the Forest of Steles in Xi'an. The guardians of national treasures in this issue, actors Li Naiwen, Zhao Wenzhuo and Xu Huanshan respectively introduced three national treasures of the stele forest: "Kaicheng Stone Classic", "Zhaoling Liujun", and "Yan Family Temple Stele". The past of Zhaoling Liujun has been recalled, and a copy of the "Zhaoling "Erjun" Restoration Record" published by the Shaanxi People's Fine Arts Publishing House has also recently been noticed by readers.
The Six Horses of Zhaoling are hidden in the Forest of Steles, of which "Fist Hair" and "Salu Purple" are replicas
Zhou Ping, the author of "Zhaoling "Erjun" Restoration Record", is one of the three experts who stood out from many stone cultural relics restoration experts in 2010 after rigorous selection and evaluation and went to the United States to restore "Erjun", which is also the first time that China sent cultural relics experts abroad to participate in the restoration of Lost Chinese cultural relics. The "Zhaoling "Erjun" Restoration Record" records the story of the "Zhaoling Liujun", the reason for the restoration of the "Erjun", the preparatory work and process. It can also enable readers to understand the past and present lives of "Fist Hair" and "Salu Purple".
Zhou Ping, graduated from Northwest University in 1995 majoring in cultural relics protection engineering, is currently the vice president and researcher of Shaanxi Provincial Institute of Cultural Relics Conservation. He has presided over and participated in a number of scientific research projects of the Ministry of Science and Technology and the State Administration of Cultural Heritage, as well as the compilation of 5 national standards and 8 standards and industry standards. He has presided over a number of national key cultural relics protection units and collection cultural relics protection and restoration projects such as the clay sculptures of Tianjin Dule Temple and the assessment of the disease and stability of precious cultural relics of the Forest of Steles Museum. In 2010, as a volunteer, he went to the United States to restore the "Erjun" of Zhaoling Tombs, and successively served as the leader of a number of Chinese and foreign cultural relics protection and restoration projects.
A restored still of the Zhaoling Liujun "National Treasure" inside the Sima Gate north of Zhaoling
Discovery of new fragments and comparison of stone carving materials
From June to November 2003, the Shaanxi Provincial Institute of Archaeology (now the Shaanxi Provincial Institute of Archaeology) conducted a comprehensive excavation of the sima gate site in the north of The Tang Zhaoling In Shaanxi Province, and newly discovered some fragments of the "Zhaoling Liujun". After on-site matching, experts believe that the largest piece of the fragment belongs to the hind thigh of the green horse, and the large piece of the palm with delicate leg hair is the hoofed wrist part of the front horse leg of Shivachi. The remaining three fragments of the "Zhaoling Liujun" are temporarily in doubt and are included in the Forest of Steles Museum in Xi'an. Due to the needs of the work, the Forest of Stone Steles Museum in Xi'an showed the volunteer team the three fragments found in the later archaeological excavations in Zhaoling. After the museum agreed, the volunteer team used plaster to copy the fragments and brought them to the United States for comparison, thus establishing friendly contact with the United States.
Fragments of the "Zhaoling Liujun" that exist in the Forest of Steles
According to historical records, the stone carving material of "Zhaoling Liujun" mainly comes from a kind of bluestone in Fuping County, Shaanxi Province. This kind of bluestone is a kind of ink jade produced by Fuping. According to the "Chronicle of Fuping County", ink jade is "heavy in color, delicate in texture, pitch black as ink, smooth as jade, and extremely prestigious." At the end of the Ming Dynasty and the beginning of the Qing Dynasty, one of the famous "Three Li of Guanzhong", Li Yindu, a native of Xuezhen town, Fuping County, also said in the preface to a poem entitled "Tang Ling Mo Yu" that "there are cave stones under the Tang Tombs, named Mo Yu." Take the engraving of the tablet, A in the world". His poem says: "The giant moraine Cui Wei has a million layers, and the Tang family has a tomb on the inside." Qingling ink jade swirled along, and the light of the seal was everywhere. "From Qianxian In the west to the Eighteen Tombs of Tang in the east in Pucheng, except for the tombs dedicated by Tang Gaozu, they are all tombs according to mountains. The "Tang Tomb" mentioned in Li Yindu's poem refers to the Phoenix Mountain where the Tomb of Emperor Zhongzong of Tang is located.
As early as the Han and Tang Dynasties, Fuping ink jade was famous for its delicate texture and tough texture, black and shiny color, crisp sound of tapping, thick and flawless stone layer, and resistance to acid and alkali, cold and heat, weathering, etc., and became the preferred stone for stone carvings in front of the tombs of emperors and nobles. Therefore, the stone stele stone carvings in front of the Tang Tombs and their funerary tombs are mostly made of Fuping ink jade. Among the famous monuments of past dynasties, such as Li Si's "Carved Stone on Yishan Mountain" in the Qin Dynasty, the "Cao Quan Stele" in the Eastern Han Dynasty, the "Emperor Fu's Birthday Monument" by Ouyang Qing in the Tang Dynasty, Liu Gongquan's "Xuan Secret Ride", and the Qianling "Wordless Stele", etc., are all carved in Fuping ink jade.
In the preliminary preparations, the restoration team made a special trip to The Palace Town in Fuping to visit local stone carving craftsmen, understand the processing technology of traditional stone carvings, and look for stones similar to the "Zhaoling Liujun" stone, and made stone powder to be used to repair the "Erjun" on the spot.
Learn about traditional stone carvings
Processing of stone powder
Went to the United States to repair the "Two Jun"
On May 10, 2010, the working group went to the University of Pennsylvania Museum and saw the long-awaited "Erjun" near the wall on the east side of the Chinese exhibition hall.
One of the back braces of the fist hair
The fist is filled with glass beads
According to American experts, since the Zhaoling "Erjun" officially entered the Museum of the University of Pennsylvania in 1920, it has not carried out any protection and restoration, nor has it carried out relevant scientific research work, but zhou Xiuqin, a researcher at the museum, has conducted a lot of historical research on its "loss". Therefore, the "Erjun" also basically maintained its original situation: the "Salu Purple" fragment was 4 large pieces, and the "Fist Hair" was broken into 6 large pieces. However, a large amount of black attachment remains on the surface, and there are traces of artificial repair. In view of the above situation, the first work of the US experts is surface cleaning, removing old repair materials, replacing support devices, anchoring, and installation and fixing.
Before the purple repair
Before the repair of the fist hair
According to the preservation status of stone carvings and the results of analysis, the black pollutants on their surface are mainly oil pollution, which may be left over from packaging and transportation or later repair process. Therefore, the cleaning is mainly based on hot steam cleaning, with scalpel removal, cotton swab cleaning and other means, the cleaning effect is more ideal.
After the surface cleaning of the "Erjun", the American experts opened the original repair and bonding of the "Erjun" and removed the residual glue of the section and the materials previously repaired. Through the analysis of the residual glue of the cross-section, it is concluded that the bonding material is a binder of the phenolic resin class. Due to the long use time, the aging phenomenon is obvious and the adhesion strength is low. During the demolition process, American experts found that the previous repair method was to use wooden supports inside the stone carvings, then repair them with plaster, and finally color the surface for aging. There's also an interesting vignette: In the first half of The Fist, experts find a local New York newspaper from 1966. It can be inferred from this that after the "Erjun" was shipped out, it was repaired in the United States.
Demolition of old restoration materials
A newspaper that was used to repair the "Fist Hair"
After the surface cleaning of the "Erjun", American experts reinforced the stone carvings. For larger stone fractures, stainless steel anchor rods are used for reinforcement internally and then bonded with epoxy resin. Previously, in order to improve the overall stability of the stone carvings, American experts designed the connection device and connection method of the fractured parts of the stone carvings, and the newly made support device fixed the two stone carvings into three parts.
As mentioned above, China has found a number of "Zhaoling Liujun" fragments, of which several pieces of "identity doubts" were made of plaster replicas in this trip to the United States for comparison, experts found that there is a piece of the top of the saddle of the fist hair. After comparison, it was found that it was very consistent with the section of its saddle. As shown in the following figure:
Determine the scheme: from restoration with newspaper and linen to restoration with similar materials carved in rough
After understanding the current situation of the "Erjun", the three restoration experts had an in-depth discussion with the American experts, and after understanding the previous repair problems and the technologies, materials and methods in the restoration, a scientific completion plan was formulated for the actual problems of the "Erjun".
Discuss with US experts on the spot
Scholars first learned about the materials used by Erjun in the past restoration, and found that some paper materials such as newspapers, calendars and museum profiles were mixed in the restoration part, and the past repairs mainly used wood as a supporting material, and then used gypsum to fill and repair, in order to prevent gypsum cracking, coarse hemp was added to wrap.
Materials used for previous restorations: newspaper, plaster, strips of wood and linen
Regarding the completion of the "Erjun", experts from China and the United States conducted detailed communication and consultation, formed a completion plan, and consulted three domestic experts, Wang Danhua, Huang Kezhong, and Lu Shoulin. Finally, a consensus was reached: the three major parts of the newly made bracket of "Erjun" were not connected; the remaining small cracks were surface repaired; the missing part was selected as the internal support and the surface was completed; and the material of the completion was mainly similar to the original stone carving material.
Purple: Red is the completely fractured part, green is the crack, crack
Fist hair: red is the completely broken part, green is the crack, crack, yellow is the missing part
Expert opinion
Start the restoration of "Erjun"
Regarding the principle of the completion of the "Two Juns", scholars from both sides have determined the following:
1. The principle of least intervention;
2. The principle of reversibility;
3. The completed material should be safe and durable;
4. The completion of the missing parts is based on the previously unrepaired situation, and only the shape of the stone carving is made, and the details such as characters and horses are not completed;
5. The complete position should not only conform to the principle of scientific protection and restoration, but also show the historical beauty of cultural relics;
6. For the parts of large-scale completion, light materials should be used to reduce the pressure of the complete position on the stone carving and the overall weight of the stone carving.
According to the scheme of experts from both China and the United States, the completed materials are mainly divided into the following types: one is the screening of local small crack completion materials; the other is the screening of completed materials for larger cracks (about 0.8 to 1 cm); and the third is the selection of completed materials for missing parts. For the completion of local small cracks, after the American experts bonded the "Erjun" and supported by mechanical devices, some small cracks remained on the surface of the stone carving, which were mainly distributed in the "Fist Hair" horse's head, front legs and horse buttocks, and the "Salu Purple" cracks were fewer, mainly concentrated in the rear horseshoe.
According to the current situation of small cracks, the completed materials mainly include binders, additives, and natural mineral pigments. First of all, the repair experts screened the binder in the laboratory, and the binder mainly considered factors such as good reversibility, strong adhesion, aging resistance, and strong operability. According to the early repair experience and laboratory tests of American experts, 45%-55% of the acetone solution of PARALOID B 72 was selected as the binder. The additive uses stone powder brought from the town of Fuping Palace in Shaanxi Province. As mentioned earlier, the "Zhaoling Liujun" was originally carved on a bluestone slab weighing more than three tons, and this bluestone is a kind of ink jade specialty of Fuping. After the binder is determined, a supplementary material screening test is carried out in the laboratory to determine the final ratio of the additive to the natural mineral pigment.
After the completion of the material is determined, the method of repair is relatively simple. First, in order to improve the adhesion of the completed material to the stone section, the section was first brushed with a 30% acetone solution of PARALOID B 72. Then use a scalpel and a small scraper to slowly fill the small cracks with the configured completion material. After the area to be repaired is completely dried and cured, the surface of the surface is colored and aged using natural mineral pigments to harmonize with the surrounding colors. However, the actual operation is more difficult, and the technical requirements for the repair personnel are high. Because the cracks are small, they are not easy to handle when filling. At the same time, if the filling is not complete, the surface is prone to depression and cracking.
After the head of the fist is completed
For larger cracks, it is mainly considered that the cracks are wider and deeper, and the completed material is relatively thick and directly filled, which is easy to lead to insufficient filling inside the cracks and surface cracking. Therefore, it is necessary to replace it with other materials that are highly operable, easy to fill, and do not occupy the volume and weight. It was finally determined to use 30% PARALOID B72 to blend with high-performance glass beads. High-performance hollow glass beads are a hollow ball powdered ultra-light inorganic non-metallic material, which is a widely used and excellent new lightweight material developed in recent years, with a general density of 0.20-0.60g/cm3, particle size between 2-130μm, with light weight, large volume, low thermal conductivity, high compressive strength, good fluidity and high filling performance.
The mixed glass beads are pressurized to fill the inside of the crack, the filling surface is about 1 cm lower than the stone carving surface, until it is completely cured, the surface is repaired with a complete material, and finally the coloring and aging treatment is carried out.
Glass beads filled
After the larger cracks are completed
What to do about large missing parts
Scholars have found that the "fist hair" is more missing, mainly distributed under the hind hooves and the upper part of the horse's tail. The thickness of the stone carving under the horseshoe is 24 cm at the thinnest point, 39 cm at the thickest point, the longest part is 50 cm, and the widest part is 26 cm, and the shape is obliquely trapezoidal. The upper part of the horse's tail is 22 cm at its thinnest point, 38 cm at its thickest, and the missing part is 82 cm longest and 45 cm widest, in the shape of a glyph. These areas are missing large, if you directly use the complete material to repair, one is thicker and easy to crack; the second is larger; the third is that the bond with the section is not strong. Therefore, a support device should be made inside the full complement to play a role in fixing and supporting. At the same time, in order to reduce the gravity of the stone carvings in the entire position, the support device should be made of lightweight materials.
After several discussions and material screening, the foam was finally selected as the internal support material from wood, light aluminum, foam material, plexiglass, and foam plastic. At present, there are many manufacturers of foam plastics in the world, and after consultation, investigation and research analysis, experts use polypropylene (PP) foam plastic boards for food packaging produced by Pacific Company in Illinois, USA. The packaging material has 775 closed holes per square centimeter, does not contain harmful blowing agents such as Freon, is recyclable, light in weight, good air permeability, excellent ability to absorb impact energy, good heat insulation, flame retardancy and dimensional stability, and strong corrosion resistance. Microfoam XPS developed and produced by Pactiy complies with the relevant regulations of the U.S. Food Packaging and Drug Administration (FDA) and can be used in all food packaging.
First, the PP foam plastic board is cut into the shape of the missing part, the thinner part uses two layers of foam plastic plate, the thick part uses 4 layers of board, using epoxy resin bonding and fixing; second, in order to increase the adhesion of the foam plastic board to the complete material, improve the mechanical strength of the foam plastic board, a layer of epoxy resin layer is bonded on the plastic plate and its surface is brushed; third, a 15% PAROIDAL B 72 brush is used on the stone carving section to make a bonded isolation layer. The foam plastic plate is then bonded with the stone carving with epoxy resin, and the foam plastic layer is about 1.5 cm lower than the surface of the stone carving; finally, it is filled with the configured completed material and colored for aging.
Surface brushing, filling
After the missing area is completed
The stone brought to the United States is compared with the "Erjun" section
Field work scenarios
The interior is filled after the foam material is made
After the surface of the foam material is bonded with epoxy resin, the material is filled with complete material
After restoration, it is displayed in the exhibition hall
"Records of the Restoration of the "Erjun" of Zhaoling" edited by Zhou Ping
(Note: The content is synthesized from the "Zhaoling "Erjun" Restoration Record")
Editor-in-Charge: Lu Sijia