The Science of Art Restoration


Ashley Zhao, Staff Writer

When you think of what it takes to become an art conservator, you’d probably first imagine that it requires knowledge in art history or practical experience in the process of painting or drawing. But in actuality, many prospective art conservators have the same undergraduate chemistry requirements as pre-med students. As stated by Yale University Art Gallery chief conservator Ian McClure, “any graduate [art] school [with] chemistry graduate or physics graduate applicants [regards them] with a great deal of interest because they have the capacity to go into the practical side and the research side.” By having a solid background in science, a conservator can have a fundamental grasp on the increasing number of scientific techniques necessary for restoring art. 


During the 1800s and 1900s, the practice of art conservation was commonplace, and even paintings done by the Old Masters (European painters working between the Renaissance and 1800) were often redone to match the taste of the time. One example of this is painter Johannes Vermeer’s “The View of Delft”, which was found to “have been modified about 50 times” according to McClure. He elaborated on this statement said that the “more famous the painting, the more often it [has] been redone because people simply cannot keep their hands off it.” But compared to present methods, art conservation from past times was far from scientifically precise and was found to be quite harsh and severe. Old conservation manuals suggested covering entire paintings with wood ash and then wiping it off with water, which would cause an extremely harmful alkaline substance to form on the painting. Even as recently as twenty years ago, conservators were still using solvents that are now considered toxic by hand. 


But nowadays, modern conservators will use a variety of technology to determine in a non-invasive way the remaining original areas of a painting and understand how the painting had been treated in the past. An initial analysis will be taken with x-rays to learn more information about the painting’s composition. These x-rays will allow the conservator to form an outline based on differing absorptions. McClure elaborated that “lead white paint, often used for figures and faces, is very absorptive so you can see them and also areas of missing paint because even translucent paints become more absorbent with added layers.” Infrared imaging would be used next to take a look at the original drawings and losses of paint. Recent technological advancements in art restoration include a camera with fixed wavelengths, allowing conservators to pinpoint types of drawings at certain wavelengths. In the past, millimeter square portions of a painting would be removed to identify varnish layers and different pigments used. By doing this, however, pieces of the painting are removed and the overall piece is less illuminated than a modern scan of the entire painting. 


Once a coherent picture of the original picture is created and all previous attempts to preserve and renew the art have been identified, the next step would be to remove the discolored varnish and layer restoration paints if possible. New technology called Raman spectroscopy helps conservators to determine the exact composition of the varnish. In this method, a monochromatic wavelength will strike the material surface and then be transmitted or reflected. A small portion will be absorbed by the molecules of the material and will be reiterated at a slightly different frequency. The frequency change for any given wavelength of light is measured and is found to be characteristic of the molecules, thus allowing for characterization of the varnish. After identifying the varnish and removing the outer layers, the varnish can be repaired so that any restoration work is separate from the original painting. As a result, McClure explained that “in the future, anything that removes the varnish will remove all the restoration.” New kinds of varnishes are also being developed and researched, with additives like UV absorbers being mixed in to prevent discoloration or be more stable and easily removable. 


Many well-known museums, like the Metropolitan Museum of Art, the Museum of Modern Art, and the Getty Gallery each have scientists dedicated to developing special techniques for art conservation. So the next time you visit a museum, you can keep in mind all the wonderful scientific discoveries that conservators do to reveal the artist’s original vision in each painting.

Photo Courtesy of YOUTUBE.COM