Modern sculptures are made of a wide range of materials including metals, stone, wood, synthetic resins, plastics, etc. With the onset of the 20th-century, a great variety of industrial materials were introduced, which artists actively incorporated in their works to better express their intent. Understanding the properties and the aging processes of materials used in works of art is a difficult task. Performing conservation treatments without fully understanding the behavior of these materials could potentially cause more damage to a work. Therefore, advanced research and extensive testing is required before any treatment of modern sculptures.
Sculptures installed outdoors are prone to undergo physical and chemical deterioration due to fluctuations in temperature and humidity and the effect of UV rays and air pollutants. Metal sculptures are highly susceptible to corrosion caused by one or the combination of these external factors resulting in structural and aesthetical problems.
The effect of the environment, the ageing of materials, and human actions can be causes of physical deterioration of modern sculptures. These deteriorations range from cracking and flaking of paint to fracture or loss of component materials.
Painted sculptures installed outdoors are exposed to a multitude of external factors and usually for an extended period of time. Paint discoloration caused by UV rays is one of the most common damages observed. The extent of discoloration varies depending on the geographical location and orientation of the sculpture in relation to the sun. Severe discoloration could be a distracting element for the viewer and a sculpture in such a condition may fail to articulate the artist’s intention.
As contaminants can accumulate and incur damage on the surface of sculptures, regular maintenance is important for such works. Surface cleaning and coating are carried out on a regular basis as a preventive measure. Modern and contemporary sculptures made with diverse materials are treated with caution after considering their unique characteristics and determining the method and scope of cleaning so as not to cause damage to the works. Bronze sculptures installed outdoors are coated with wax and/or resin after cleaning for protection from environmental factors, and are monitored regularly to maintain optimum conditions.
Physically damaged sculptures are consolidated by repairing fractured elements through jointing, filling and stabilizing the problematic area. Media art and kinetic artworks, in particular, require regular inspection and maintenance so that they can function as intended.
In the case of painted sculptures, cracking, peeling and discoloration of the paint layer are some major examples of damage. In such cases, the sculpture is repainted locally or entirely, through careful matching of the original color and texture. An intact layer of paint acts as a protective coating for the support material which could be metal, plastic, stone etc. If it is deemed that the original paint applied by the artist or a previous conservator is susceptible to damage, then a different kind of paint with verified durability is selected for repainting. Thus, prior to a repainting process, information is collected from the artist, and/or the artist’s estate, as well as paint manufacturers to decide on the painting materials and the painting method, in collaboration with the owner of the work, and curators.