The Art institute has cutting-edge conservation facilities headed by world-class conservators and scientists. What many people might not realize is how ingenuity and creativity are as important as tools and technology. Artworks are made from many kinds of materials, so they often require innovative approaches to determine the best conservation treatment, and since so many of these materials are derived from animals and plants, our conservators and scientists sometimes source unusual products in their search to discover these inventive solutions.
How unusual? Let’s start with seed pods, insects, and bowling alley wax, and see where that leads.
SEED PODS
While studying four painted masks from Burkina Faso, West Africa, we encountered some unfamiliar materials. Dating from the late 19th to early 20th century, these masks are carved in a soft wood and decorated with geometrical patterns in black, red, and white paint.
When analyzing the black paint, we identified tannins, natural substances present in many plants and often associated in our daily life with a strong tea or red wine. Fieldwork accounts mentioned that the black paint was made using seedpods from a native plant (Acacia nilotica), so to better understand the colorant’s composition and properties we decided to purchase the same seed pods and try to prepare the paint in the lab. We were fortunate to have the opportunity to discuss the process with artist Abdoulaye Ouedraogo from Boni, Burkina Faso, who had extensive experience in producing masks using traditional methods. He explained the laborious process of boiling the seeds and pods together in water over several days to produce a thick, black extract, rich in tannins, for use as a paint.
making paint from seedpods and seeds
Pod and seeds from Acacia nilotica (left).
Pods and seeds being boiled in water (right).
While our efforts to manufacture black pigment from raw materials was not as impressive as an experienced artist, the process was fundamental to confirming the nature of the colored material, as well as to developing an analytical tool that confirms the use of traditional techniques in similar masks.
Bugs
Another example of the importance of collecting reference materials is carmine, a bright red colorant derived from female cochineal insects of the Dactylopius coccus species. We purchased these insects in order to analyze the carmine used by Pierre-Auguste Renoir in the painting Madame Léon Clapisson. These cochineal bugs live as parasites on the nopal cacti, commonly called prickly pear, found in Mexico, Central and South America, and it takes around 70,000 individuals to produce one pound of pigment. (You might be more familiar with it than you realize: many red or pink foods and drinks contain the same cochineal-based colorant!)
Beetles before and after
Cluster of female beetles laying their eggs in a prickly pear cactus (left).
Dried bodies as they would be used to extract the red colorant (right).
Carmine had been used as a dye and pigment by the Aztec for centuries before it was imported to Europe in the 16th century, where it became a common colorant used by artists, including Impressionists such as Renoir. This vivid red tends to lose its color over time when exposed to light, a phenomenon evident in Madame Léon Clapisson. When our colleagues in paintings conservation removed the painting from its frame, they noticed that the edges covered by the frame—and protected from the light—were a much brighter red than the exposed areas of the painting’s background. Analysis in the scientific lab revealed that the background had been painted with carmine.
Effects of light on Renoir’s carmine
Detail of preserved color under the frame and how it fades in light (left).
Imagine how vivid the background of the painting might have looked when Renoir painted it (right).
Detail of preserved color under the frame (left) and the faded color (right)
Photo by Kelly Keegan
Pierre-Auguste Renoir
changing lanes
Believe it or not, Bowling Alley Wax, manufactured by the BWC Company, became a product that we frequently ordered back in 2015 and 2016—a total of nine cases containing 12 16-oz cans to be exact. During these two years, the arms and armor collection was being prepared for the debut of the Deering Family Galleries of Medieval and Renaissance Art, Arms, and Armor. Bowling Alley Wax was chosen as a protective coating because it’s the perfect blend of solvent and waxes (microcrystalline and carnauba), easy to apply in several coats, and buffs to a shine fit for a knight at a joust.
Protecting armor
Former object conservator Philippa Beesley, at work on the arms and armor collection—note the can of wax to the right.
putting a pin in it
Insect pins, the kind used by entomologists and other folks who study insects, come in many sizes and are available in stainless steel or black enamel. While we don’t have entomological collections, our textile conservators regularly use these fine pins to hold and align textiles during a treatment. Specifically, the 000 size pin, which is very fine, can be delicately inserted between the threads of an artwork without damage while still providing stability. Insect pins are also used to mount objects for display. Conservators will sometimes paint the heads of the pins to match the color of the artwork to make them as undetectable as possible. Next time you explore textiles in our galleries, we dare you to find them!
mystery MOUTHWASH
One day years ago, Frank Zuccari, the former head of Conservation, submitted a receipt from Walgreens for a bottle of Listerine mouthwash. It was slightly unclear why the department head was asking to be reimbursed for dental products. The bottle, in the original yellow-gold formula color, remained in Frank’s office until he retired. Today’s painting conservators speculate Frank had it on hand for killing mold, which can grow on canvases exposed to high levels of humidity or water. One of the key ingredients in the original Listerine formula was thymol, a naturally occurring compound, also found in thyme and other plants, that has strong antimicrobial properties.
the list goes on
There are surgical blades and needles used for taking micro-samples from artworks. There are glass dental plates, which textile conservators use as weights to reduce creases in fabric; these plates are made of shatter-resistant glass with smoothed, beveled edges, and because they are transparent, conservators can see any issues on the artwork when using them. And did we mention the old VCR, TV, and computer parts and tools needed to repair time-based media artworks, whose technologies are now considered obsolete but whose operation is essential to keeping the artwork functioning properly? And, of course, the requisite badger tail brushes and porcupine quills for scratch-free cleaning … the list goes on.
This gives you an idea about how our inventive conservators and scientists apply their skills to understand artists’ materials, studying their use, properties and how they changed over time. This is turn provides information that is crucial for helping us decide how best to provide treatment to artworks, making them available to future generations.
Last but not least, it also explains some of the strange receipts we submit when tax time rolls around.
—Clara Granzotto, Andrew W Mellon Associate Conservation Scientist, Conservation and Science, and Jann Trujillo, administrative coordinator, Conservation and Science
Read more to learn about a porcupine quill in action.
