How are chemicals used in art restoration?
Art restoration is a partnership between art and chemistry. Starting with the natural pigments used on the very first rock paintings, chemicals have been used by artists since the most ancient times. Today, modern chemicals, such as solvents, resins, fungicides, and silicones, are essential to preserve the world’s artistic and cultural heritage.
Chemistry and physics are the basis in determining the most appropriate restoration processes for paintings, sculptures, textiles, or even ancient monuments. Sophisticated chemicals are used to restore, preserve and protect everything from Michelango's sculptures and frescoes to the terracotta warriors of Qin Shi Huangdi or the Statue of Liberty. There are about 120 to 140 different substances or mixtures of substances that are used in restoration processes! That’s why an art conservator needs to have a solid scientific background to know how to use them.
Art conservator as chemistry expert
The restoration process starts with an overall evaluation of the work. The art conservator, in close cooperation with an art historian, indicates the context and period when the artwork was created, and studies the techniques and materials available at that time, as well as the ageing mechanisms. He/she must identify the components of the work, such as pigments, colourings, additives and varnish, before investigating their properties and chemical behaviour.
Besides human abuse, art objects mainly suffer from sunlight, humidity and poor maintenance with the wrong products. Chemistry helps us to understand why a work of art is deteriorating, how this happens in the long run, and how it can be prevented.
Art conservators also need to identify the best techniques and materials to protect art objects which are exhibited around the world. They must consider any preventive conservation issues, such as the environmental conditions, temperature and lighting during the travel, the most appropriate equipment to handle the object, and the conservation conditions of a collection.
Preservation of the world’s cultural heritage
Take as an example high quality solvent-based coatings that are used to safeguard the world's cultural heritage, old castles, churches and monuments, and modern architectural wonders. In St. Petersburg, Russia, extreme climatic variations and pollutants generated by the large urban environment have seriously damaged the facades of the world-famous Winter Palace. After careful investigation, a special solvent-based coating is applied in the restoration process, providing a strong protective layer which is not only waterproof and resistant but also self-cleaning.
This topic is discussed further in the Xperimania online chat “How are chemicals used in art restoration?” on 5 February 2009, at 14.00 CET (in French).
Prior to this chat a conference on “Art and Chemistry” will take place on 28 January 2009 at the Maison de la Chimie in Paris. More information on this event is available on www.uic.fr