Inside the Library That Holds the World’s Rarest Colors

Abigail Cain
Nov 2, 2017 9:26PM

I’m standing with conservation scientist Narayan Khandekar in a glass-ceilinged laboratory on the fifth floor of Harvard’s art museum, surrounded by paintings in various stages of analysis and repair. In front of us, a life-size portrait of King Philip III of Spain by 17th-century court artist Pantoja de la Cruz rests on an easel. From the monarch’s patterned pantaloons to his neatly combed hair, the work is painted almost entirely in shades of brown.

Scientifically speaking, Khandekar tells me, brown pigments are typically rather dull. “They’re usually the same thing: raw umber, burnt umber,” he explains, naming two types of naturally occurring minerals that everyone from cavemen to Rembrandt have used to make paint. “So browns are really boring to analyze.”

But Khandekar’s research indicates that one of these pigments may be less monotonous—and quite a bit more macabre—than the others.

Mummy Brown is precisely what it sounds like: a pigment produced by grinding up the flesh of Egyptian mummies. It appeared as early as the 16th century; production continued until the 1960s, when the supply of embalmed bodies finally petered out. While the historical record confirms that artists did purchase the paint, Khandekar says researchers have yet to find an artwork in which the pigment is definitively present. But a newly surfaced studio inventory for de la Cruz lists Mummy Brown among his supplies. If accurate, this portrait will be the first confirmed use of the pigment in a work of art.

Narayan Khandekar stands in front of a 17th-century Spanish painting that may contain Mummy Brown. Photo by Tony Luong for Artsy.


Khandekar heads the Straus Center for Conservation and Technical Studies at Harvard, a role he’s held since 2015. Together with a team of 20-odd scientists and conservators, he oversees the study and preservation of roughly 250,000 artworks and objects—from Ancient Greek coins to Egyptian amulets to Constantin Brancusi sculptures—owned by the university’s museums.

For more than a decade, he’s also served as the custodian of the historic, roughly 2,500-piece Forbes Pigment Collection. Although public access is restricted, the row of floor-to-ceiling cabinets on the museum’s fourth floor—stocked with a literal rainbow of powders in glass bottles of all shapes and sizes—are clearly visible through a glass-walled atrium.

Alongside a few tubes of Mummy Brown are other pigments whose origin stories are practically legend. Tyrian purple, an ancient Phoenician dye that requires 10,000 mollusks to produce a single gram of pigment, is said to have been discovered by Hercules’s dog as he snuffled along the beach. Indian yellow, purportedly made from the urine of cows fed only on mango leaves, was banned by the British government in the early 20th century on the grounds that its production constituted animal cruelty. Ultramarine, a vivid blue made from lapis lazuli mined in Afghanistan, was once more precious than gold.

Vials of pigments held by the Forbes Collection. Photo by Tony Luong for Artsy.

But the Forbes Collection is far more than a cabinet of curiosities. It’s the most colorful piece of a larger effort to modernize the care and conservation of works of art in the United States—a 20th-century project largely spearheaded by a man named Edward Waldo Forbes.

Forbes, the grandson of poet Ralph Waldo Emerson, graduated from Harvard in 1895. Like many of his well-to-do peers, he set sail for Europe to experience firsthand the great classical, medieval, and Renaissance works he’d learned about in class. But for Forbes, seeing was not enough. He started to acquire art, loaning (and eventually donating) his collection to Harvard’s newly-founded Fogg Museum.

But purchasing early Italian works, the young man quickly realized, could be a risky business. Aware that American collectors were often less educated in art-buying than their counterparts across the Atlantic, underhanded European dealers began to exploit these easy marks. “There just weren’t as many early Italian paintings in America as there were in Italy, for example,” explains Khandekar. “So the buyers were not as experienced with what they were seeing. And so you had people trying to sell over-restored stuff, forgeries, things that were pastiches.”

Photo by Tony Luong for Artsy.

Photo by Tony Luong for Artsy.


Forbes, says Khandekar, was a “very, very careful buyer.” But even he was fooled once or twice—a Benozzo Gozzoli painting of the Virgin and Child, while partially authentic, turned out to have been painted over twice by modern restorers. A thorough cleaning left both figures faceless. The more time Forbes spent examining art, the more certain he became that a strong technical knowledge of an artist’s materials and process could help determine “what art is true and beautiful” (and, by extension, what was a forgery).

In 1909, Forbes was officially appointed director of the Fogg. His oft-stated dream was to create a “laboratory for the fine arts,” one that applied scientific methods to the works of the Old Masters. “What he did was establish the first major conservation department in the country,” says Khandekar. “It was making decisions that were accountable, transparent, recorded.”

Certain pigments have legendary origin stories. Ultramarine, a vivid blue made from lapis lazuli mined in Afghanistan, was once more precious than gold.

George L. Stout, hired in 1928 as the head of the conservation department, developed the first systematic condition report for artworks in order to track their physical state. “Every museum has a condition report now,” says Khandekar, “but it all stemmed from what Stout did.” That same year, Forbes recruited chemist Rutherford John Gettens to join the department. He would be the first scientist to ever work at an American museum.

Like Gettens before him, Khandekar is a trained chemist. He received a Ph.D. in organic chemistry from the University of Melbourne before changing course and pursuing a career in art conservation. I asked him if the two fields were really that similar. “Well, analyzing it is. You use all the same tools, you use the same techniques,” he says. “Just, instead of analyzing mud and biofilms, you’re analyzing paintings.”

The Gettens Cabinet at Harvard’s Straus Center for Conservation and Technical Studies. Photo by Tony Luong for Artsy.

Historian Sarah Lowengard, author of a 2006 book about color production in 18th-century Europe, notes that the practice of pigment collecting is hard to date precisely. “It’s entirely possible that Mr. or Ms. Caveperson hoarded ochres and nicely charred sticks with which to draw,” she says. But she links “an interest in collecting pigments for a scientific or natural-philosophical purpose, such as the Forbes Collection, to desires to collect anything and everything. The legitimization of this desire is familiar as cabinets of curiosity,” small groupings of rare or remarkable artifacts that are generally dated to the 17th and 18th centuries in Western Europe.

An early example of scientific pigment-gathering is the case of Giovanni Francisco Vigani, a chemistry professor at Cambridge who purchased a set of materials to use in medicinal remedies in 1704. His collection included a number of pigments that remain at the British university today. Another significant grouping of pigments was amassed by the Dutch Hafkenscheid family, who supplied painting materials to manufacturers and pharmacists in the 19th century. They sourced materials from across the globe—France, Turkey, Brazil, even Dutch Guyana—and today, approximately 370 pigments from their collection are held in the collection of the Teylers Museum in the Netherlands.

Forbes began gathering pigments in 1910. At first, he focused on the palettes of 15th-century painters, helpfully documented by Italian painter Cennino Cennini in a 1437 handbook. Forbes began his quest in London with a chunk of azurite, eventually purchasing yellow ochre, reddish-brown hematite, and even planting madder root in his own garden to make red.

View of the fourth-floor conservation laboratory at the Straus Center. Photo by Tony Luong for Artsy.

He would continue to travel across the world and collect colors, often from practicing colourmen—professional paint-makers who had begun to proliferate in the mid-18th century as a reaction to the increasing complexity of art supplies. An unpublished memoir penned by Forbes details some of his international adventures. “It reads like Fitzgerald and Hemingway without the literary pretense,” Khandekar says, describing a trip to Japan during which Forbes visited colourmen in both Tokyo and Kyoto. Later, Khandekar shows me a cardboard sample box out from one of the cabinets; each glass vial is labeled in Japanese characters with phonetic English translations underneath.

The pigments Forbes brought back to Boston were subjected to a battery of microchemical tests conducted by Gettens. The results of these analyses are recorded in the chemist’s 1942 book Painting Materials: A Short Encyclopedia, which he co-authored with Stout. Even 70 years later, it “is still the go-to volume,” Khandekar says. “It has all kinds of interesting things in it, but what everyone remembers is these sections on pigments which give their history, their chemistry, their uses. It’s an incredibly useful resource.”

What makes the Forbes Collection so prominent today, says Lowengard, is its positioning within a prestigious, resource-rich university. “With only anecdotal evidence to support me,” she notes, “I’d say that many collections are made with research as a goal, but time, expense, knowledge, access to appropriate workspace and to publication streams mean they end up as more personal, and more as things of beauty than critical objects in the search for truth.”

Photo by Tony Luong for Artsy.

Indian Yellow is a rare pigment, purportedly made from the urine of cows fed only on mango leaves. Photo by Tony Luong for Artsy.

Forbes retired from the Fogg in 1944, leaving behind more than 1,000 pigments. But without the director as a guiding force, the collection fell by the wayside. Pigments continued to be added, says Khandekar, but “it wasn’t in any systematic way.” After Gettens, there wouldn’t be another scientist hired by the museum until the 1970s.

As collecting slowed at Harvard, however, the number of available pigments (and binders, the ingredient in paint that allows pigment particles to stick to both each other and the canvas) was skyrocketing. Synthetic materials had begun to infiltrate the world of commercial paint production as early as the 1930s, and technological advancements in the following decades had only accelerated this trend. Artists soon began to incorporate these newly developed paints—often intended for houses or cars or boats, rather than art—into their own work.

The Forbes Collection could be described as a conservator’s crystal ball: offering glimpses into the aging process for any materials that might make their way into a work of art.

To understand how these modern paints would age, other institutions started their own collections of pigments and other materials. For the J. Paul Getty Trust, it happened in the 1990s, when the Getty Conservation Institute moved from an off-campus office in Marina del Rey to a new, larger space on the institution’s main Los Angeles campus. Today, their catalogue contains close to 15,000 items, 2,310 of which are pigments—including a set of microscope slides containing tiny samples pulled from the Forbes Collection’s larger stores of lead white or burnt sienna, for instance. (Subsets of the Forbes Collection can be found in more than 20 laboratories worldwide, from the Library of Congress’s Preservation Office in Washington, D.C. to the National Research Laboratory for Conservation in New Delhi to the Metropolitan Museum of Art in New York.)

The Getty focuses largely on gathering modern materials, notes conservation scientist and collection manager Arthur Kaplan. “The large majority of our collection is things from the last 30 years, since our collection was established. We’re primarily collecting commercial materials because we don't have people who could just go mine pigments or collect tree sap for us, for example.” Since the Getty’s collection doesn’t have a designated budget, Kaplan notes, most of their collecting is driven by specific research projects within the institution that require difficult-to-source materials.

Photo by Tony Luong for Artsy.

For Harvard, it also took a particular project—in this case, several purported paintings by Jackson Pollock—to jumpstart the modernization of its long-neglected pigment collection. In order to analyze these 20th-century artworks, Khandekar recalls, “we needed a whole set of standards, and we realized that we didn’t have them in this collection.” The Tate, which had been building its own set of modern pigments, sent 250 samples to Harvard to help with the project. As it turned out, three of the so-called Pollocks were splattered with pigments that weren’t commercially available until the 1960s and 1980s—years after the artist’s untimely death in 1956. It wasn’t conclusive proof that the paintings were forgeries, but it did confirm that they had been significantly altered by someone other than Pollock himself.    

Since that project concluded in 2007, there’s been a renewed interest in fortifying the Forbes Collection for the 21st century. Recent additions include plastic baggies of Day-Glo pigments often used by nun-cum-Pop artist Sister Corita Kent in her prints; Vantablack, the world’s “blackest black,” which sparked controversy when it was licensed solely to sculptor Anish Kapoor; and artist Stuart Semple’s response, the world’s “pinkest pink” that can be purchased by anyone but Kapoor.

Narayan Khandekar holds up a bottle of synthetic ultramarine pigment. Photo by Tony Luong for Artsy.

Photo by Tony Luong for Artsy.

These pigments no longer come from colourmen. Instead, they are sent in by companies or by independent pigment experts. (One man, a former Sun Chemical employee and author of a tome on pigments, sent a cache of powders he’d stumbled upon in his garage.) And there are still focused projects that bring in new pigments. For example, the Forbes Collection added 25 traditional Australian ochres several years ago—a project that demonstrates how the study of pigments can sometimes re-write art history.

For many years, historians believed that the introduction of Australian art centers in the 1970s had radically altered the working processes of Aboriginal bark painters. Instead of grinding their own natural pigments, the thinking went, these native artists started to use commercially produced materials like acrylic paint and Belgian linens provided by the institutions. “Some people consider this a real divergence from the tradition that was going on before,” Khandekar says. But after analyzing a range of bark paintings, the researchers discovered that Aboriginal artists were in fact using silver roof paint likely sourced from the keepers of a nearby lighthouse as early as the 1920s. In the 1940s, they were making black pigments from dry cell batteries (even though naturally-occurring black ore and charcoal were also available).

“What that says is, if the color is available, the artists will use it,” Khandekar notes. Rather than disrupting traditional Aboriginal bark painting techniques, the introduction of art centers offers “just one more example of these innovative artists adapting to what’s available and using it for their own practice.”

Historic it may be, but the Forbes Collection deals as much with the future of artworks as the past. It could almost be described as a conservator’s crystal ball: offering glimpses into the aging process for various pigments, binders, and any other materials that might make their way into a work of art.

Harvard’s museum scientists have advised working artists ever since Forbes’s tenure, when the U.S. government approached the Fogg in 1935 for help with its newly-founded Federal Art Project (FAP). Officials wanted the murals and other works created using federal dollars to stand the test of time, but it was often difficult for them to distinguish between low- and high-grade paints. Gettens helped to launch Boston’s Paint Testing and Research Laboratory, which functioned from 1937 to 1941, analyzing paints for their durability and quality. Many of these tests still exist today in what is known as the Gettens Cabinet—an 80-year-old, wooden filing cabinet tucked away on the fourth floor of Harvard’s art museum. Each drawer is hand-labeled and full of paint samples, some of which have been aging for more than half a century.

You can’t ask a dead artist a question. It’s important to ask all this stuff while you can.

More recently, Khandekar has advised New York City-based artist Jennifer Bornstein during a residency at Harvard. Many of her works involve crayon rubbings of three-dimensional objects. “We were able to analyze the blue crayon that she was using,” Khandekar says, “and using one of the standards here, we found out it was carnauba wax. So we were able to say, ‘Yes, it is very stable, and there’s no problem with you using it.’”

Khandekar once spent a “nice day” with Ellsworth Kelly “talking about how he paints, how he decides on color, about the issues of what’s the right color, what’s the right finish on the top—all these kinds of things.” That sort of information is invaluable to collect in the present because, as Khandekar wryly points out, “you can’t ask a dead artist a question. That’s why it’s important to get in there and ask all this stuff while you can.”

It’s certainly too late to ask de la Cruz about Mummy Brown. Even with the studio inventory list in hand, it will be at least six months before Khandekar can confirm that the portrait of King Philip III contains the elusive pigment. As the director of the Straus Center, he’s got plenty on his plate—including a class he teaches for Harvard graduate students on technical conservation.

Pigments collected by Edward Forbes during a 1932 trip to Japan. Photo by Tony Luong for Artsy.

Forbes himself taught a class at Harvard in the early 20th century, a course students nicknamed “Egg and Plaster” after their assignments to mix paint from yolks and plaster miniature frescoes on the wall of their professor’s basement. Khandekar’s class may not be as intimate, but his students still walk away with a better understanding of the material aspects of art. “It’s an opportunity for the students to learn that a work is not just an image on a screen, that it actually is made of something,” he says. “It’s made by somebody and it’s got a physical presence. It’s got heft.”

Works of art can be transporting, even transcendent. Sometimes, as Mark Rothko wrote in 1947, they’re downright miraculous. But as Forbes, Gettens, Stout—and now, Khandekar—are acutely aware, they’re also objects. Each sketch, painting, sculpture, or carved relief is subject to the deleterious effects of time. And what use is a miracle if it’s falling apart?

Abigail Cain


A previous version of this article incorrectly named the painter of King Philip III’s portrait as Rodrigo de Villandrando. The portrait was painted by Pantoja de la Cruz. The article also incorrectly called carnauba wax “canalda wax.”