Whether or not you know the difference between an Italian Caravaggio and a Jackson Pollock painting, you’ve likely visited a museum or old church at some point and run across art that “just spoke to you.” Unfortunately, time is not kind to these historic treasures. Dirt, mold, pigment changes, and yellowing varnish take their toll, obscuring details and distorting colors. Until recently, restoring cherished artwork required extensive, meticulous effort and great skill. Now, advances in technology are being used to assist art conservators (who stabilize and preserve works of art) and restorers (who clean and repair art) in restoring and preserving beloved classic pieces more efficiently and with great accuracy.
Before any work begins, X-ray analysis provides information about how a painting was composed, while infrared imaging enables a conservator or restorer to see the original drawing and paint loss. These processes eliminate the need for the old technique of removing millimeter-square areas of varnish to identify layers and different pigments used, potentially damaging the artwork. Conservators at the National Gallery of Art in Washington, D.C., used such imaging techniques to help in the restoration of El Greco’s Saint Martin and the Beggar.
Laser technology is also being used in art restoration. For example, laser spectroscopy is used to analyze the composition of varnishes, enabling the right solvents to be used for removal and helping identify the age of paintings. Lasers can also be used to clean paintings and statues using a wavelength that removes dirt and varnish with minimal interaction with the layer underneath. This technique – similar to that used for tattoo removal – has been used to great effect in removing the dark film covering of frescoes in the bakers’ niche in the Catacombs of Domitilla in Rome, Italy, as well as restoring the black carbon drawings by Leonardo Da Vinci in the Sala delle Asse at the Castello Sforzesco in Milan, Italy.
Digital technology is playing a huge role in the restoration process, with advanced photography techniques such as reflectance transformation imaging (RTI) providing new insights. RTI’s sophisticated software creates a single image compiled from multiple digital photographs taken under light projected from different directions. The new digital image looks like a two-dimensional picture, but actually captures a subject’s true surface shape and color down to the single pixel level. Significant computer processing power is then used to study every angle and minute detail of this high-precision digital image in preparing for restoration of degraded sections.
Conservators from the San Francisco Museum of Art were able to identify specific causes of damage on works such as Scenes of Life of Christ by Penicaud, a centuries-old enamel on glass painting. By determining whether the cause was a crack, a flake of paint that moved, or salts on the surface, conservators could better decide which conservation technique to use. The technology also enables removal of color from the image on a computer screen to see the extent of any damage more easily and learn more about the techniques of the artist.
Technology is also helping “restore” paintings without a single brush stroke. Scientists working with Harvard Art Museums used digital technology to restore a set of old photographs of a series of delicate paintings by Rothko, known as the Harvard Murals. This approach was then used to create, pixel by pixel, a “compensation image” that was projected directly onto the original canvas, “restoring” the original painting for viewers. A similar technique, coupled with electron spectroscopy to analyze paint from a section of Renoir’s Madame Léon Clapisson, has enabled art lovers to see the masterpiece in its original colors, without laying a brush on the canvas.
Thanks to technology enabling these powerful techniques and new insights, both serious students of art and casual viewers can continue to admire stunning masterpieces for generations to come.