<Conservation of Metal Artifacts>

Metal artifacts are constructed from various metals, and are passed down to us by either by hand or by the means of excavation: both their original forms and lifespan are subject to damage in time.  Conservation processing of metal artifacts is a work that aims to prolong the lifespan of the artifacts: by restoring the damaged original form and maintaining a stable preservative environment to prevent damage.

Cause of Damage

Metal artifacts are subject to corrosion, due to metal's property of returning to its original oxide state.  Corrosion of metal artifacts vary in nature by the material and the environment that the artifacts endure. Corrosion may cause not only aesthetic damage, but also structural damage as well, depending on the cause of corrosion and its progression.

<Conservation Processing for Metal Artifacts>

♠ Scaling and Examination

Identifying the material(composition), the inner structure and the cause of damage in artifacts using survey equipment such as X-ray or microscope; the current state of the artifacts and the survey results are recorded and archived.

♠ Foreign Substance Removal

In order to return the artifacts into their original forms, foreign substances, such as dirt or corrosion, are removed using various tools and chemicals.

♠ Stabilization

Further corrosive activity is prevented and the possibility of re-corrosion is minimized by suppressing or removing corrosive elements, such as chloride.

♠ Reinforcement

Reinforcing the weakened materials of the artifacts and creating a protective film, thereby sealing off the artifacts from corrosive elements such as oxygen or moisture and preventing accelerated damage.

♠ Repair and Restoration

Detached or broken off parts are re-attached to their original position; lost parts are restored to their original condition, as long as the original form can be inferred.

♠ Color Matching

Coloring the re-attached/restored parts to match the general tone of the artifact.

♠ Storage

The procedure and the results of conservation processing are recorded, aiding the future management of the artifacts. Metal artifacts are stored in an environment of 45% relative humidity or less, and are vacuum-sealed within film layer if necessary.

<Conservation of Pottery and Earthenware>

Pottery and earthenware refer to the articles that are shaped from natural clay and then fired.  Depending on the firing temperature, the artifacts are categorized as earthenware, pottery, stoneware and china. While these are more chemically stable than other artifacts, but they are more prone to physical damage.

The reason behind conservation-processing the artifacts that are damaged in such a physical way is to restore the artifacts into a state that is more meaningful as exhibitions—the state that draws more historical interest.

Cause of Damage

Primary damage to pottery and earthenware comes from physical harm; terrain-pressure during the time of deposit or carelessness during excavation and transportation leads to cracks and greater damage. Another possibility is a damage from improper conservation processing conducted by non-professionals.

There are environmental factors as well. Earthenware recovered from high-salt area may have been damaged due to the sodium's crystallization during the repeated wet-dry cycles. Freezing and natural disasters such as flooding, fire or earthquake are also common causes for damage.

<Conservation Processing for Pottery and Earthenware Artifacts>

♠ Preliminary Survey

Manufacturing style or patterns are surveyed either through naked eye or microscopic examination. Advanced technology such as X-ray can be used to identify inner fractures or degree of restoration required. Such investigation becomes the basis for determining the type of conservation processing to be applied.

♠ Cleaning

A process of removing surface contaminants using distilled water or chemical solutions: devices such as ultrasonic cleaner or steamer are used.

♠ Reinforcement

Soft pottery, made from softer clay, or weakened pottery/earthenware are reinforced: either by applying diluted hardening agent or soaking in it. The artifact is then dried in room temperature.

♠ Repair

Adhesive is used to re-attach broken shards onto their original position. Preliminary attachment to determine the shape and the order of repair is always conducted before the actual adhesive-using repair: re-attachment is a delicate procedure in which there must be no mistake in the earlier stage.

♠ Restoration

Restoration materials such as synthetic resin is used to restore the damaged parts into their original form. Various data related to the artifact is reviewed, and experts are consulted if necessary.

♠ Color Matching

Restored parts are colored using brushes or airbrushes. If the piece has a gloss finish, varnish is used to give an enamel-like effect.  Parts with historical significance, such as patterns, are restored as far as the restoration does not warp the significance.

♠ Finishing

All the solutions and techniques used during restoration and other notes are recorded in detailed writing or photography, preparing for possible future re-processing.

<Conservation of Wooden Artifacts>

Wooden artifacts range from wooden architecture to mundane items such as furniture, farming equipment, stationary or instruments.

In order to restore and preserve the original form of the wooden artifacts, a detailed examination of the manufacturing methods, materials, current state and causes of damage are necessary; any conservation processing much be based on the survey.

Cause of Damage

Wooden artifacts are easily damaged due to temperature, humidity, biological factors and physical factors.

Most of the damage is caused by complex interactions among many factors, rather than a single element.  Rapid shift in temperature and humidity causes deformation, and the growth and feeding activity of molds and harmful insects decompose the wooden structure.  Also, the physical factors destroy the form of the artifacts.

<Conservation Processing for Wooden Artifacts>

♠ Pre-processing Survey

Stereoscopic and biological microscope, X-ray machine and qualitative/quantitative analyzer are used to identify the species of the wood, material, structure and condition, setting the plans for processing.

♠ Dry and Wet Cleaning

Dust and foreign substances that contaminate and discolor the surface are removed through dry or wet cleaning.

♠ Corrosion Compound Removal

Removing the corrosion compound from the decoration made from iron, copper or copper alloy.

♠ Reinforcement

Dislocated shards or fractured/split parts are repaired and reinforced using natural adhesives such as glue or fish glue.

♠ Restoration

Restoration must be conducted using the original material and manufacturing technique in principle; however, other artifact-safe materials may be selected if necessary.

♠ Color Matching

The restored parts are matched in color, using the painting ingredients from the original period.

♠ Post-processing Survey

Following the conservation processing, the procedure and other notes are recorded. The artifacts are photographed and measured in detail.  Wooden artifacts that have gone through conservation processing are put in appropriate preservative environment. When the artifacts are displayed in exhibits, they are disinfected for insect control and preservation, preventing any damage from harmful life.

<Conservation of Paper and Written/Drawn Artifacts>

Written/drawn artifacts are based on paper, silk, ramie or hemp materials: ink or coloring pigments are used to write or draw on the materials.   Depending on the convention, the artifacts were made into books, albums, paper rolls, scrolls or folding screens.

The conservation processing for paper and written/drawn artifacts involve a restoration process of removing the cause of damage and recovering the original condition.

Cause of Damage

○ Damage due to change in temperature/humidity and discoloration from light

○ Physical damage and loss form tearing, folding and bending    ○ Biological damage from staining, molding and insects

○ Separation from backing paper due to weakened adhesion of starch glue

○ Peeled or powdered coloring pigments due to weakened adhesion of glue

<Conservation Processing for Paper and Written/Drawn Artifacts>

♠ Pre-processing Survey

Artifacts are examined with microscope, X-ray or infrared lighting, and the conditions of the pigments, silk or paper are surveyed, setting the direction for conservation processing.

♠ Dry-cleaning and Disassembly

Dust or other foreign substance on the surface of the painting are softly brushed off. The six pieces, held together by thread, are disassembled then re-assembled based on the form of the painting and the streak of the silk.

♠ Wet-cleaning

The surface of the paintings is reinforced with protective paper, and the contaminants are removed by carefully spraying filtered water.

♠ Adhesion Reinforcement for Pigments

Once the glue's adhesion weakens, the pigments are peeled off or powdered. The adhesion is reinforced by applying 2 to 3 coats of rabbit glue.

♠ Repairing the Lost Parts

The area where the silk is missing is repaired using identically structured silk. In order to balance the physical tension that is put on the silk, electron-deteriorated silk is used.

♠ Paper Backing

Backing is a process of attaching a layer of paper onto the rear of the painting for reinforcement.  Mulberry paper, dyed with alder tree berries, is attached using 3 to 5 coats of starch glue.

♠ Scroll-decoration of Portraits

Hand-weaved lotus-flower shaped silk is dyed using whole-leaf Indian hawthorn and alder tree berries, decorated into the traditional scroll format of the Joseon period portraits.

<Cultural Artifacts Given a New Life>

<Museum Conservation Environment Management>

Museum conservation environment management aims to protect the artifacts by surveying the surrounding environment when the artifacts are exhibited, stored or moved, and minimizing the effects of environmental elements.

To this end, the natural or artificial elements around the artifacts that may be harmful are surveyed/monitored using various devices; appropriate measures are taken to minimize potential damage.

<Temperature and Humidity>

Minimizing the damage from physical and chemical influences by maintaining a proper temperature and humidity; consideration must be given to the material nature of various artifacts that are made from singular or complex materials

<Illumination>

Minimizing the damage from light energy such as discoloration and color change

<Biology>

Using nature-friendly methods such as IPM (Integrated Pest Management), and preventing the biological damage to the artifacts

<Airborne Contaminants>

Maintaining a pleasant environment for both the artifacts and the visitors, and preventing damage to the artifacts, by monitoring the contaminants from both the external and internal sources.

<Artifact Analysis>

Artifact analysis natural-scientifically identifies the characteristics of the artifacts by analyzing the manufacturing technique, the geographical origin, the date of production and the paleoenvironment. The analysis provides archaeologically or historically significant data, and becomes the basis for artifact management and conservation processing.

Data Acquired through Artifact Analysis

Examines and scales the composition elements of the artifact, identifying the material.  Material identification is especially necessary in case of excavated artifacts or collected artifacts made from complex material.

Also, for those artifacts that has internal fractures and many layers, internal expansion and investigation are conducted to identify the internal structure and manufacturing technique.

In addition, carbon dating is used to estimate the date of origin in artifacts that contain carbon, and the origin of the ingredients used to manufacture the artifact can be identified through trace-element analysis.

<Cases of Artifact Analysis>

♠ Coloring Analysis of the 19th Century Peony Painting

Based on the coloring analysis using XRF, digital microscope and spectrum colorimeter, the following ingredients were identified: ink stick for black; lead power for white; sulfur, brass, litharge and organic yellow pigment for yellow; cinnabar, red lead, red ocher, organic red pigment and organic purple pigment for red; malachite for green; and lazurite for blue.

♠ Analysis of the White Porcelain Shard Recovered from Seoul-area Kiln Site

Based on the composition analysis and statistical processing through ICP-MS, XRD and SEM-EDS, it was estimated that the Goryeo porcelain kiln site produced white porcelain from clay of various blend, and that the site had an identical clay-source with the southern-Seoul kiln site.

♠ Composition Analysis of the Late Joseon Period Buddhist Painting's Background

A small sample was obtained from the background area of the painting of the Buddha and the Ten Kings. Following the composition analysis and form-observation of the sample using FT-IR and SEM, the background material was identified as ramie and cotton.

<Artifact Replication>

Replication denotes the process of creating a new object that is identical to the original object in shape.  Artifact replication has the purpose of conducting research and education while keeping the original safe, when the artifact has great historical or artistic value, or is weakened due to time and has a potential to be damaged.

The replicas are considered to be of less value than the original, due to its diminished effects and the viewers’ negative perception of the item as a forgery. A high-quality replica can be only made with a thorough understanding of the artifact: how the item was used and manufactured in the time of the original making.