How Scientific Methods are Used in Art Restoration
By Senior Conservator Peggy Van Witt
© 2010 Peggy Van Witt. All Rights Reserved.
In recent years, the art community and the scientific community have joined forces. This often odd pairing of individuals has become an essential relationship in the world of art restoration and art conservation. Without the application of chemist’s skills and knowledge, many of the art restoration and art conservation techniques we use today to save some of the world’s most highly valued art wouldn’t exist – and neither would many of these precious works of art.
Scientists, mostly chemists, are employed by some of the most famous museums and galleries around the world as art conservators. Scientists who work in museums and art galleries engage in a broad range of art conservation and art restoration activities. They conduct many investigations into various types of artwork, most often studying the chemical composition and structure of artifacts, what environmental factors may be contributing to their deterioration (often called corrosion products) and the materials used in previous attempts to conserve or restore the piece of art.
Other scientific endeavors of these art conservation artists include checking the effects of the museum's environment on the artwork, which includes monitoring the air for pollutants using very technical and complicated scientific tools, measuring relative humidity, biological activity such as the growth of mold spores or insects. To detect such pollutants, scientists employed by museums as art conservator’s use specialized tools. To detect pests, as previously mentioned, scientists will often use such high-tech tools as ultraviolet scanners and visible illumination procedures.
Many artifacts are sensitive to destructive environmental agents in the museum and art gallery atmospheres. Drastic fluctuations in relative humidity will cause dimensional changes in wood furniture, polychrome sculpture, and panel paintings. These changes often lead to cracking and splitting of the wood with loss of painted surface decoration, not to mention a serious loss of monetary value. High relative humidity can lead to mold growth and foxing on books and prints, while low relative humidity will cause photographic prints and films to become brittle.
Though most of the work done by scientific art conservators for art conservation and art restoration involves the use of analytical techniques, many other areas of chemistry, biology, physics, and engineering are involved. These activities include polymer chemistry, kinetic studies, imaging methodologies, biodegradation studies, dating methods, computer modeling, metallographic, and corrosion engineering. The harmony between the scientific community and the art world has become quite obvious.
The ways in which scientific art conservators approach an art conservation or art restoration is usually divided into two classes: those that provide an image of the entire object, known as holistic examination or just a section of it, and those which analyze a small point on the object, which may or may not involve sampling. Whenever possible, the scientific art conservators will use nondestructive methods during the analysis, art conservation or art restoration.
The most commonly used method of holistic art conservation and art restoration science is x-ray radiography, where variations in the density and average atomic number of the sample attenuate an x-ray beam, leaving a negative image on film. Like other scientific methods, the use of x-ray technology was adopted by the art world from the arena of human and veterinary medicine. Other methods, such as ultraviolet and infrared reflectance and fluorescence, are used to show areas of compositional difference indicating restoration or variation in the pigments used by the artist.
Such nondestructive methods, such as a non-required sampling, are always preferable. However, modern scientific art conservator’s methods of analysis take such a minute amount of a sample that they are in effect, nondestructive. Previous to their widespread use in the art conservation and art restoration world, needles were used on humans to inject or withdraw fluids from humans and animals. Now that the scientific community and the art world have combined, needles are used to collect paint samples from paintings or inject a small dose of varnish into a hard-to-reach area of a painting.
Science has helped greatly in the sampling arena by making the impact on the works of art so minute that it is essential nondestructive. However, the ability to analyze minute samples raises a few concerns. Many feel that such a minute sample may not be representative of the entirety of the composition of the artifact but may in fact be an inclusion or contaminant introduced in patchy or small amounts to only a section of the painting, or may have been introduced by the art conservator. With painting specimens from painted surfaces, great care must be taken to identify areas which need art restoration or art conservation.