Step behind the closed doors of the Department of Conservation and Scientific Research to see how several portraits in the Sackler Gallery’s exhibition Worshipping the Ancestors: Chinese Commemorative Portraits were restored.
Remember! These are trained professionals – don’t try this at home on your cherished family portrait of your great grandmother.
Smoke, Dirt, and Mold
Preparing for the Exhibition
Cleaning the Portraits
One example of the cleaning process that was used for many of the paintings is the treatment of the portrait of Prince Hongming (see left). After many years of exposure to dust, grime, and soot from incense, the portrait had become soiled, stained, and darkened. Also, at some time in the painting’s history, water soaked the upper right corner, staining the silk background cloth.
The surface of the painting was first cleaned with a soft brush to remove loose dirt and dust. Lightly moistened cotton swabs were then gently rolled over the painting to loosen and remove soil. Since many of the paintings are sensitive to water, great care was taken not to disturb pigments on the surface. Stained areas of the background silk were also cleaned using a vacuum table that draws water through the silk without damaging the delicate silk fiber. This process removes staining but does not endanger the pigments.
After many hours of careful cleaning, the pigments appear brighter and the surface of the painting is lighter overall. The staining in the blank area surrounding the painted image is barely noticeable. We now have a better idea of how the portrait may have looked when it was first painted.
Detail; Portrait of Prince Hongming (1705–1767). China, Qing dynasty, 1767, or later copy. Hanging scroll; ink and color on silk; image only, 200.8 x 115.4 cm. Arthur M. Sackler Gallery, Purchase—Smithsonian Collections Acquisition Program, and partial gift of Richard G. Pritzlaff, S1991.61
Consolidating Pigments and Reinforcing Creases
As a hanging scroll ages, it dries out and becomes less flexible. Repeated rolling and unrolling causes the mounting structure to crease or crack and eventually break. These creases force the pigments on the painting surface to loosen and separate from the silk support and cause paint losses in the image. The extent of this problem also depends upon the age of the painting, how frequently it was rolled and unrolled, and the quality of the materials and techniques that the artist used. For example, in this portrait of Daisan, a major leader during the early Qing dynasty (1644–1911), the animal glue binder that was mixed with the painting’s pigments more than a century ago has lost its holding strength. As a result, the pigments have become powdery and easily fall from the silk surface.
In this case, the loose (exfoliating) pigments were consolidated, or adhered in place, using a traditional animal glue binder. The solid glue was dissolved in warm water to a 1 percent concentration and applied with a brush or sprayer over the unstable pigments. This process, which takes several hours, was repeated in areas needing better adhesion. Areas where the pigments are coarse or thickly applied were consolidated using a vacuum table (see left). The table’s strong suction pulled the animal glue binder through the thick layers of pigments and into contact with the silk support beneath, thus ensuring stable consolidation.
The stabilized pigments are no longer in danger of coming (cleaving) off the surface of the painting when the portrait is handled and displayed. The creases in the mounting support are now reinforced with strips of paper applied from the back. These paper strips minimize the support’s effects and deter further damage to the painting.
Reusing or Replacing Mounting Silks
The colorful silks that are part of the backing, or “frame,” for the portraits form an important part of the painting’s history. When possible, conservators reuse old mounting silks that are in good condition and are appropriate to the painting in terms of color and age. In these cases, the silk mounting fabric is removed, cleaned, and remounted around the painting.
Sometimes the silk is simply worn or damaged beyond repair, as was the case with the portrait of Lirongbao’s wife. The old mounting silk was extremely soiled and stained. It is also torn and broken, and large pieces were missing. These silk fabrics had become so weak and brittle that they no longer support the painting safely. Even after cleaning, they could still have shown signs of wear, fading, and stains. The conservator and curator decided to remove the old mounting and replace it with new silk.
The conservator and curator selected new silk fabrics that are historically accurate and visually harmonize with the painting. Pattern, color, and the style of the mounting were all taken into consideration. For example, a bright yellow silk decorated with certain birds or dragons would be appropriate for an imperial portrait, while a more subdued tan goes well with this portrait of the emperor’s mother-in-law. Since the mounting must complement the painting, the silk is often dyed to soften colors and to make the fabric look older so it blends with the age of the painting. The fabrics are then lined with thin Chinese paper, and wheat starch paste is used to adhere the painting to the mounting. This process takes several weeks to complete.
The new mounting silks were dyed to a shade that harmonizes with the age, color, and style of this portrait. The new fabrics make a durable yet flexible mounting that both shows the painting to its best advantage and creates a safe support for the scroll’s display and handling.
Portrait of Lirongbao’s Wife (act. late 17th century).
China, Qing dynasty, 18th to 19th century. Hanging scroll; ink and color on silk; image only, 177.6 x 98.6 cm. Arthur M. Sackler Gallery, Purchase—Smithsonian Collections Acquisition Program, and partial gift of Richard G. Pritzlaff, S1991.129