By Bettina Ebert, Paintings Conservator and Researcher, Asiarta Foundation
Conservation of works of art broadly encompasses their care and treatment in order to maintain them in a suitable condition.
Works of art, and in particular paintings, are generally composed of a multitude of materials. These materials may deteriorate over time as a result of interaction with the environment, especially light and moisture. Light is important for us to be able to enjoy a work of art. However, light and oxygen from the atmosphere are involved in photo-oxidation reactions which may initiate degradation processes. Pigments can fade, while materials may yellow and disintegrate.
Other agents of deterioration include atmospheric pollutants in gaseous or particulate form. A good example of the effect of an airborne pollutant such as sulphur dioxide is revealed in our story on the conservation of paintings by Nguyễn Trọng Kiệm. Particulates in the air settle on artworks as dust, soiling the surface and altering the object’s appearance. Cleaning or dirt removal from a work of art is often a challenging process.
Artworks are also subject to microbiological processes such as mould growth, particularly in humid environments. Insects and pests may attack artworks as a source of food. Woodworm bore tunnels in wooden panels, substantially weakening them. Starch paste traditionally used in lining silk paintings is sought out by insects such as silverfish as a source of food. Insect excreta such as fly droppings on the surface of paintings will react with paint, causing damage to the surface.
Temperature and humidity also affect the degradation of works of art. Cyclic changes have the greatest effect on deterioration, while relatively stable or constant conditions are more favourable to a work of art’s long-term preservation. Many materials that make up a work of art are very responsive to moisture, and, may react to increases or decreases in humidity by expanding, shrinking, or cracking. Cyclic fluctuations in humidity will therefore substantially weaken a structure as it repeatedly adjusts to the environment by absorbing or emitting moisture in order to reach its equilibrium moisture content.
For detailed descriptions of the effect of various agents of deterioration on works of art, the Canadian Conservation Institute provides extensive information.
The conservator’s main aim is to preserve a work of art for the future. This may include examination and documentation of an object’s condition, appropriate handling and storage, as well as preventive care in the form of maintenance of a stable environment. If an object has been damaged or has deteriorated, it may require some form of interventive treatment to stabilise or restore the work of art. Conservators follow a strict code of ethics, in particular with regards to the use of methods and materials which do not adversely affect a work of art.
Depending on your areas of interest, we have sections on the conservation of oil paintings, acrylic paintings, lacquer paintings, paper and silk paintings. Please click on the appropriate section for further information.