​

TheCultural Heritage Conservation Science Center (CHCSC, Director, Jeong Soyoung)in the National Research Institute of Cultural Heritage (NRICH) under theCultural Heritage Administration of Korea completed conservation treatment for the gilt-bronze Bodhisattva statue of UnifiedSilla period which was excavated from Seollimwon Temple Site (Yangyang-gun,Gangwon-do, Korea) in October, 2015.

The gilt-bronze Bodhisattva statue(hereinafter referred to as the statue) from Seollimwon Temple Site is thelargest (38.7cm in height and 4.0kg in weight - thestatue, 14.0cm in hightand 3.7kg in weight - the pedestal) among Bodhisattvastatues whose excavationsites were exactly known, and the pedestal and halo which were carvedsplendidly remain intact, which made the statue draw great attention. CHCSCdevoted 5 years until the present to restoration for its original shape in goldcolor and determined its manufacturing technique and period when it wasmanufactured.  

At that time of excavation,the surface of this statue has been thickly covered with soil and greenish corrosion,and its right ankle has been broken and separated from the pedestal, and eventhe halo has been broken into several pieces, which required urgentconservation treatment. In response to its condition in need of conservation,the CHCSC urgently took it over from Hanbit Institute of Cultural Properties, which conducted theexcavation and survey beforehand, and started scientific research andconservation treatment from January, 2016 to December, 2020.

 First of all, the scientific research such asX-ray, endoscopy and material analysis was carried out and subsequently it wasfollowed by the process of conservation treatment in the order of corrosionremoval, consolidation, joining and restoration.
Asa result of research, the gilded layer was unstable as its form wasmanufactured with copper alloy and gilded with gold, and greenish bronzecorrosion was situated on it. To restore its original color of gilded layers,removal of bronze corrosion was required but it was firmly attached to thegilded layer. Therefore, the corrosion layer was removed one by one with meticulouscare while it was closely observed at high magnification under a microscope,which was such a fastidious and demanding process of conservation work. The corrosionremoval was the most significant process for restoring the shape and value ofthe statue, taking much time over 4 years.

Such a process led torevealing gilded layers clearly and moreover, delicately drawn ink lines on thegilded layer could be found as well. Areas with ink lines were identified at 4points from eyebrows, eyes (shapes, pupils), mustache and the rim with anelephant-eye motif by openwork on the pedestal. In particular, its pupils drawnin ink could be found beneath bronze corrosion by microscopy at highmagnification.

The statue was urgently collected on the spotof the excavation and for that reason, CHCSC could obtain important materialsleft such as paper and gold leaf from the inside and surface of the statue. Asthere were no inscriptions and only some parts of them remain, what those hadbeen used for could not be figured out.

However, from the fiber analysis to know material quality of paper, itwas identified that all of them were paper made from bast fiber of the papermulberry of Korea and by radiocarbon dating, the data of absolute ages aroundthe 7~9^th century was acquired. When considering the period when SeollimwonTemple prospered around 804 AD (the 5^th year of King Aejang), theperiod of its production was reconfirmed to be Unified Silla period.

From the research on the manufacturing process, itindicates that the statue was cast as the single-piece object with copper alloy, and marksof molding holes were found at the back of both arms from the result of X-ray andthose holes are presumed to have been plugged up with gold plates and gildedafter a casting was completed.

In addition, a high mercury content and granulargold were identified from the surface analysis of the statue, which revealedthat amalgam gilding by mixing gold powder and mercury had been applied formanufacturing it. And there were red pigments observed from the back ofdecorations on the statue as well as the back of floral decorations at the endof lotus leaves on the pedestal. Pigments were identified to have been Jinsa,Yeondan and the pigment mixed with Jinsa, and some red pigments still remain onits lips faintly.

Most of the navy pigmentsfrom hair were exfoliated by surface corrosion but dark navy pigments in someareas were identified to have been Seokcheong which was used as the oldtraditional pigment with natural minerals to make deep dark blue color from thepast.

*Jinsa (辰砂, HgS / Cinnabar): Red pigment made with mineral of mercury sulfide in red base

*Yeondan (鉛丹, Pb₃O₄ /Minium): Red pigment made by heating lead carbonate which isartificially manufactured after corroding lead

*Seokcheong (石淸, Cu₃(OH)₂∙(CO₃)₂/ Azurite): Blue pigment made with azurite

The CHCSC made its effort to restore the shape ofthe statue with HanbitInstitute of Cultural Properties through3D scans and image restoration and could succeed in restoring theoriginal shape of the statue in the end. In the case of decorations such as Bogwan, Yeongrak, Jeongbyeong besides the statue, halo and pedestal, thosedecorations were identified to have been separately manufactured and then joinedto the statue respectively. Some shapes of them were transformed during theexcavation, which made it difficult to join them for restoration.

 *Bogwan(寶冠): A crown decoratedwith jewelryor metal on the top of Buddha statues

 * Yeongrak(瓔珞): Decorations by stringingbeads with metal or gems for Buddha statues

 * Jeongbyeong(淨甁): A Water jug with a longneck, connoting offering pure water to Buddha as a symbol of mercy to relievepain and thirst of mankind

As of now, it is difficult to join the broken rightankle to its pedestal since the completion of conservation treatment this time.The National Research Institute of Cultural Heritage is planning to connect thestatue with the pedestal by digital restoration based on cutting-edgetechnology such as 3D scan data and 3D printing.

​

Attachment

1-1. Before Conservation Treatment of the Gilt-bronze Bodhisattva Statue

1-2. While RemovingCorrosion on Surface

1-3. Completion of ConservationTreatment for the Gilt-bronze Bodhisattva Statue

2-1. Before Conservation Treatment forthe Pedestal

2-2. Completion of Conservation Treatment for thePedestal

3. Back of theGilt-bronze Bodhisattva Statue after Conservation Treatment

4. X-ray Image

5. 3D Scan Image

6. Shape and Layout of the Whole Gilt-bronzeBodhisattva Statue

7. Restoration Drawing of the Whole Gilt-bronzeBodhisattva Statue

8. Right Eye Shape and Pupil Drawn in Ink

9. Magnified Bronze Corrosion Formed on Right Pupil Drawn in Ink

10. Right Eyebrow Drawn in Ink

11. Mustache Drawn in Ink and Red pigments Staying on Lips

12. Molding Holes on Back of Arm

13. Paper Pieces Collected from Insideand Outside of the Gilt-bronzeBodhisattva Statue

14. Conservation Treatment Process(Corrosion Removal from the Pedestal)

15. Conservation Treatment Process (Corrosion Removalfrom the Gilt-bronze Bodhisattva Statue