Treasures from the Color Archive

The historic pigments in the Forbes Collection include the esoteric, the expensive, and the toxic.
The hues in the Forbes Collection include the esoteric the expensive and the toxic.
The hues in the Forbes Collection include the esoteric, the expensive, and the toxic.Photograph by Jason Fulford for The New Yorker

How blue can it get? How deep can it be? Some years ago, at the Guggenheim Bilbao, I thought I’d hit on the ultimate blue, displayed on the gallery floor. Yves Klein, who died at thirty-four, was obsessed with purging color of any external associations. Gestural abstraction, he felt, was clotted with sentimental extraneousness. But, in search of chromatic purity, Klein realized that even the purest pigments’ intensity dulled when combined with a binder such as oil, egg, or acrylic. In 1960, he commissioned a synthetic binder that would resist the absorption of light waves, delivering maximum reflectiveness. Until that day in Bilbao, I’d thought Klein a bit of a monomaniacal bore, but Klein International Blue, as he named the pigment—rolled out flat or pimpled, with saturated sponges embedded in the paint surface—turned my eyeballs inside out, rods and cones jiving with joy. This is it, I thought. It can’t get any bluer.

Until YInMn came along: the fortuitous product of an experiment in the materials chemistry lab at Oregon State University in 2009. Intending to discover something useful for the electronics industry, Mas Subramanian and his team heated together oxides of manganese, yttrium, and indium at two thousand degrees Fahrenheit. What emerged was a new inorganic pigment, one that absorbed red and green light waves, leaving as reflected light the bluest blue to date. Subramanian sent a sample to the Forbes Collection in the Straus Center for Conservation and Technical Studies, at Harvard University, where it sits with twenty-five hundred other specimens that document the history of our craving for color.

Among the other blues on the Forbes’s shelves is Egyptian Blue, a modern approximation of the first synthetic pigment, engineered five millennia ago, probably from the rare mineral cuprorivaite, a soft mid-blue used for the decoration of royal tomb sculpture and the wall paintings of temples. Later, blues strong enough to render sea and sky were made from weathered copper-carbonate azurite—crystalline bright but sometimes darkening in an oil binder. In 1271, Marco Polo saw lapis lazuli quarried from a mountain at Badakhshan, in what is now Afghanistan. Laboriously prepared by removing impure specks of glinting iron pyrite, it became ultramarine—as expensive, ounce for ounce, as gold, and so precious that it was initially reserved for depictions of the costume of the Virgin. In addition to these, the Forbes Collection has a poor man’s blue—smalt made from crushed cobalt containing potassium glass, which weakens, eventually, to a thin greeny-brown gray.

“As if your first clapping faux pas wasn’t egregious enough.”

The Forbes Collection owes its existence to a belief in the interdependence of art and science, but it is also an exhaustive archive of cultural passion. A display features Vantablack, which absorbs 99.96 per cent of light, and has to be grown on surfaces as a crop of microscopic nanorods. In 2016, the sculptor Anish Kapoor saw the pigment’s potential for collapsing light, turning any surface into what appears to be a fathomless black hole, and he acquired the exclusive rights to it. An outcry from artists, who objected to the copyright, prompted the Massachusetts manufacturer NanoLab to release Singularity Black, created as part of the company’s ongoing research with NASA, to the public, and the artist Stuart Semple to make the World’s Pinkest Pink available to any online buyer willing to declare himself “not Anish Kapoor.” But Kapoor obtained a sample of the pink pigment, and used it to coat his middle digit, which he photographed and posted online for Semple.

Narayan Khandekar, the head of the Straus Center for Conservation and Technical Studies, takes pleasure in such skirmishes, secure in the knowledge that he presides over something weightier: a priceless resource for understanding how works of art are made, and how they should be preserved. The Department of Conservation and Technical Research was founded, in 1928, by Edward Waldo Forbes, the director of Harvard’s Fogg Museum from 1909 to 1944. Today, the Forbes’s vast library of color and its technical laboratories are housed in the museum’s steel-and-filtered-glass rebuild, designed by Renzo Piano. Rows of pigments in tubes, jars, and bowls are visible through the doors of floor-to-ceiling cabinets. Khandekar had the winning idea of displaying them as if unspooled from a color wheel: reds at one end, blues at the other. There are the products of nineteenth-century chemical innovation—viridian green, cadmium orange, and the chrome yellow with which van Gogh was infatuated but which, over time, has begun to darken his sunflowers. But at the heart of the Forbes Collection are the natural pigments that were the staples of painters’ inventories before chemically synthesized paints replaced the impossibly esoteric, the dangerously toxic, the prohibitively expensive, and the perilously fugitive.

Among those relics is Dragon’s Blood, reputed in antiquity and in the Middle Ages to have got its vividness from the wounds of dragons and elephants locked in mortal combat. The pigment actually owed its intense redness to the resin secreted from trees growing on the islands of Socotra and Sumatra, especially the rattan palm and the Dracaena draco. The Forbes’s sample is now a dusty rose—not so unlike the nineteenth-century pigment called la cuisse de nymphe emue (“the blushing thigh of an aroused nymph”)—having faded, most likely, from exposure to high light levels. Even in the early fifteenth century, the Italian painter Cennino Cennini warned in his practical manual, “Il Libro dell’Arte,” that artists beguiled by the pigment’s reputation should “leave it alone, and do not have too much respect for it; for it is not of a constitution to do you much credit.” Better to stick to madder root, red ochre, or the red-lead minium that had been in use since classical antiquity.

Other Forbes specimens have better preserved the poetic mystique of their origins. There is a murex shell from the Eastern Mediterranean, a quarter million of which were needed to make a single ounce of Tyrian Purple, the color used in the Roman Republic to edge the togas of the powerful. There is a loaf of toxic tawny-red cinnabar. (Buy it in solid cakes, Cennini advises, lest some scoundrel has adulterated the stuff with brick dust.) There is the copper-arsenite Scheele’s Green, synthesized at the beginning of the nineteenth century and more dazzling than traditional verdigris, the green-blue patina given off by corroded copper. A later variant of Scheele’s, Paris Green, equally toxic and even brighter, was so cheap to produce that it coated Victorian wallpapers, children’s toys, and—despite early evidence of its toxicity—even confectionery. Following Napoleon’s death, in 1821, some Bonapartists put it about that the British had poisoned their hero by having him sleep in a green room, the paper releasing arsenic vapors in the damp sea air.

A conservation coördinator searches among the Forbes Collection.Photograph by Jason Fulford for The New Yorker

Also on display are two tubes of Mummy Brown, made from the rendered gunk of the Egyptian dead, thought to be rich in the bituminous asphalt used in embalming and as protection against fungal decay. By the sixteenth century, Mummy was believed to cure illnesses as various as gastric pain and epileptic fits, and the flourishing trade in Mummy led to countless tombs being sacked and broken-up mummies sold to suppliers. Druggists and colormen—as preparers and venders of artists’ materials were known—often shared the same inventory and the same occult reputation for possessing exotic secrets. Bitumen, a cover-all term, was prized for its tawny glow, but the popularity of the pigment had much to do with the nineteenth-century taste for the Oriental macabre. History paintings of the kind fashionable in the eighteen-thirties and forties were gravy-brown, as if conferring period authenticity. There was cuttlefish sepia and burnt umber, but if Turner needed a loamy richness he reached for Mummy.

The pigment’s vogue was short-lived, however. At the middle of the nineteenth century, Laughton Osborn advised, in his “Handbook of Young Artists and Amateurs in Oil Painting,” “There is nothing to be gained by smearing our canvas with a part perhaps of the wife of Potiphar.” When the painter of historical scenes Lawrence Alma Tadema told the Pre-Raphaelite painter Edward Burne-Jones that he was going to see pieces of mummy before they were turned into pigment, Burne-Jones, according to his wife, Georgina, snorted that the name of the pigment was just a childish fancy. On being assured that the mummy was real enough, Burne-Jones insisted on giving his own tubes of paint a burial in the garden. In fact, as Alison Cariens, the conservation coördinator for the Straus Center, explained, scientists have found no DNA in the Forbes’s samples of Mummy to suggest that it contained human bones, but the biological material may have degraded beyond reliable analysis over the millennia. In any case, she added, humans were often accompanied by mummified animals on their journey to the afterworld, so that a tube of Mummy Brown might well contain the remains of crocodiles or cats.

The shelves of the Forbes Collection also hold a plethora of pigment sources, including cuttings of red-madder root and minute silvery bugs heaped in a glass bowl like a crunchy bar snack: Mexican cochineal, scale insects that swarmed on prickly-pear cacti, and whose crushed bodies produced the lustrous carmine crimson that so excited Caravaggio, El Greco, and Rubens. I stuck my head inside a cabinet to get a close look at the rocks of the arsenic sulfides realgar and orpiment, blazes of flame orange locked within the crystals. “Don’t breathe, don’t touch,” Cariens warned. (Cennini, who wrote that orpiment was “very good for painting on shields and lances,” also cautioned against “soiling your mouth with it, lest you suffer personal injury.”) Farther along the row was a grayish-greenish wrinkled baseball, sliced open to reveal a yolk-bright Indian Yellow. In Christian iconography, it was gold that signified the aura of sanctity, but, as Baroque masters experimented with the effects of extreme light and dark, the hunt for a deep, light-fast yellow became urgent. The cheapest, most widely available yellow glaze was made from unripe buckthorn berries and wasn’t sufficiently long-lasting for the likes of Rembrandt, who turned to the pale Lead-Tin Yellow, or massicot, for the luxurious costume of Lieutenant van Ruytenburch, in “The Night Watch.” In the early eighteenth century, antimony, combined with lead, known as Naples Yellow, became the most popular version of the hue.

Around the same time, Europeans in India noticed the rich, glowing yellow used for wall paintings and Mughal book illustrations. Botanical pigments like saffron and turmeric had been used in Persian and Turkish art for centuries, but this was more vibrant. The first samples of Indian Yellow, available in Bengal, Bihar, and centers of Rajput painting like Jaipur, were known by many Indian names: piuri, purrée, or gogili—a corruption of the Persian term gaugil, meaning “cow-earth.” The amateur artist Roger Dewhurst recorded using it in 1786, and, by the early nineteenth century, Indian Yellow had become a crucial component of the Romantic palette. Turner used watercolor washes of it to convey the limpid radiance of Venetian dawns and sunsets. His infatuation occasionally led him astray. In his portrait of Jessica, Shylock’s daughter, which was bought by the Earl of Egremont, she stands in front of a wall so screamingly yellow that one facetious critic described the subject as “a lady getting out of a large mustard pot.”

The ingredients of Indian Yellow, which arrived in little parcels at the London docks, apparently from Calcutta, were a mystery. The smell, either interestingly pungent or rank depending on the sensitivity of your nostrils, seemed to offer a few clues. To some, it had a distinct whiff of castoreum, the secretion from a gland close to the anus of beavers, which is still sometimes used in commercial ice cream as a substitute for vanilla and raspberry. Others were sure that the origin of Indian Yellow was to be found in the urine of camels, or water buffalo. After a chemical analysis in the eighteen-forties found no nitrous traces in the pigment, some argued that the dye probably originated in a plant such as the Mycelium tinctorium, which is notorious for its pissy odor.

To get to the truth of the matter, Joseph Hooker, the director of Kew Gardens, sent T. N. Mukharji, an expert in the materials of Indian arts, to the village of Mirzapur, in the Bihar region. There, as Mukharji wrote in an account published in 1883, he discovered a sect of gwalas, or milkmen, who fed their cattle mango leaves; the cattle’s urine, when evaporated in earthenware pots set over a fire and then baked in the sun, produced the precious yellow powder. Cows are sacred in Hindu culture, and the ones Mukharji had seen were, he wrote, “very unhealthy.” Mukharji’s account apparently led the British-Indian government in Bengal to ban production of the pigment at the turn of the century. Doubts about Mukharji’s story remain. Victoria Finlay, the author of “Color: A Natural History of the Palette,” found no record of the pigment’s ban in the archives, nor did she find, when she travelled to Mirzapur around 2002, any local memory of cows being fed on mango leaves. Was this yet another fable in the great treasury of color lore? In her book, Finlay writes, “When I think of Indian Yellow, I will always wonder whether the explanation that I have heard is reality or merely a reflection of reality, and whether this story is simply an example of somebody gently, and literally, taking the piss.”

A selection of pigments from the Forbes Collection.Photograph by Jason Fulford for The New Yorker

For Edward Waldo Forbes, pigment hunting and gathering was not just a matter of creating an archive of lost or languishing color. It was about the union of art and science. His pedigree embodied the paradox: one of his grandfathers was the railway magnate John Murray Forbes; the other, the transcendentalist philosopher-poet Ralph Waldo Emerson. With a Massachusetts schooling, culminating, inevitably, at Harvard, Forbes was a typical product of the generation who believed that Gilded Age materialism could be redeemed by the “Western civilization” that the social critic and art professor Charles Eliot Norton eulogized in the art-history lectures that Forbes attended as an undergraduate. The moral purpose of that civilization was the conversion of raw wealth into beauty and humanism. Guided by this principle, Forbes read English at Oxford for two years, and travelled through Europe, spending time in Italy. Still, he resented the condescending European assumption that the New World would never really rise above breathless cultural tourism. Serious art history was supposed to change that, and in 1900 Wellesley College became the first in America to offer a degree in the subject. But teachers at Wellesley and Harvard had to make do, for the most part, with plaster-cast reproductions and lantern slides.

In Rome, the twenty-six-year-old Forbes bought his first Italian painting: a half-ruined, flaking altarpiece attributed to Girolamo di Benvenuto di Giovanni del Guasta—the first of many acquisitions that he made with the intention of lending them to his alma mater. Aware that Yankee buyers in Europe were being treated as easy marks, Forbes saw that, if he was to avoid being swindled, he needed to educate himself in the material construction of Old Master paintings. The claims of art and science that had shaped Forbes’s education seemed to converge. To experience the power of great painting and the romance of the original art work, as Ruskin passionately argued, the viewer must be able to recover, even to imaginatively reënact, the artist’s moment of creation. For Forbes, the varnish intended to preserve works of art had trapped them beneath a yellowing skin. But what lay beneath, exactly? And how to recover a painting’s innocence without corrupting it further?

Modern archeology, with its fastidious excavations, seemed to offer a promising model. There were also Victorian manuals on the material composition of pigments—including “The Chemistry of Paints and Painting,” by Arthur Herbert Church, one of the first scientists to hold a position at the Royal Academy of Arts, in London. In 1928, as the director of the Fogg, Forbes invited a Harvard chemistry professor, Rutherford John Gettens, to create and run a lab in its new building. Gettens’s legacy is a cabinet, near the pigment collection, that contains thousands of slides, each showing how the shade of a paint might age naturally depending on its binding medium: egg yolk, egg white, the whole egg, oils.

For Forbes, the precondition for understanding an art work lay in identifying and analyzing the materials from which it was created. In addition to collecting pigments, Forbes planted madder in his garden at Gerry’s Landing, on the Charles River, and taught the lab section of his courses at home, where students could brush gesso and lime on an assigned patch of wall or, using pigments ground at M.I.T., take a stab at Boston fresco. In pursuit of the authentic, he had resins sent from Singapore and Indonesia, and Japanese woodblock colors from his brother William, the American Ambassador to Japan in the early nineteen-thirties. Forbes set aside a small collection of these pigments in a cabinet for his students to inspect.

Khandekar allows the public to examine a small vitrine of pigments, but the main collection can be glimpsed only from across an atrium courtyard. Many of the pigments inside are still used for research. In 2007, Khandekar and his colleagues analyzed the paint in three works previously thought to have been by the Abstract Expressionist Jackson Pollock, who died in 1956, revealing a yellow pigment, PY 151, that was developed in 1969, as well as a red pigment mixed in a brown paint that was not developed until 1974, and also other media and binding not available until the nineteen-sixties and seventies. Analysis of a life-size portrait of King Philip III, of Spain, from the workshop of the court painter Juan Pantoja de la Cruz, circa 1605, which was acquired by the Fogg a century ago, revealed traces of cochineal carmine and quite possibly Mummy Brown, much darkened and deteriorated—the palette thus encompassing an empire of pigments from Egypt to Oaxaca.

A chunk of the mineral malachite, used to make the pigment Malachite Green, sits beneath a portrait of Mark Rothko taken by Herbert Matter and borrowed from the New York Public Library’s picture collection. The red spectrum is a reference to Rothko’s Harvard murals, in which the Lithol Red has faded.Photograph by Jason Fulford for The New Yorker

Khandekar was also part of the team behind the famous restoration of the Rothko murals commissioned by Harvard in 1962. Installed in the Holyoke Center, a modernist tower, the paintings were subjected to an unfiltered flow of light and the kind of casual abuse inflicted by chair backs and college catering until 1979, when conservators, curators, and university administrators, recognizing the extent of the damage, took them down. The murals were next exhibited in 1988, and Harvard received a barrage of criticism for their neglect. Some conservators have blamed the paintings’ discoloration on Rothko’s use of rabbit-skin glue as a binder; others, on his choice of Lithol Red, a low-cost powder pigment. Khandekar, who oversaw the research on the Harvard murals, suspects that their extreme fading was due to Rothko’s mixing of a calcium-salt red with synthetic ultramarine to make the purplish indigo that he so loved in his saturnine years.

Physical restoration using those colors would have made matters worse, Khandekar explained, not least because the pigments would have bled directly onto the raw canvas. Therefore, he and a team of scientists and conservationists devised a new approach to conservation, involving the projection of colored light over the paintings. When illuminated, the paintings appeared in their undamaged condition. To achieve this effect, the Straus Center’s conservation scientist Jens Stenger designed a digital “color map” of both the original paintings and the damaged murals, taking into account the fact that the various parts of the murals had degraded at different rates, according to their exposure to light. Stenger’s light projections, which restored the appearance of the original colors, had to be absolutely precise, but the result, shown in 2014, was a revelation.

This is just the kind of project that gives Khandekar and his associates at the Straus Center the greatest satisfaction. Khandekar, who was born in Sydney, is a modern personification of the Forbesian mission: a hard-core scientist converted almost mystically to the imperatives of art. His first degree was in organic chemistry. But, after a visit to the National Gallery of Victoria, Khandekar told me, “I asked myself, ‘How can a scientist spend his life with art?’ ” The conservation course at the Courtauld Institute, in London, offered an answer. Khandekar went on to practice conservation at the Hamilton Kerr Institute at the Fitzwilliam Museum, in Cambridge, England, then at the Getty Conservation Institute, in Los Angeles, before, in 2001, going to the Straus Center.

Khandekar and his lab colleagues talk about pigments in a way that is at once technically sophisticated and disarmingly naïve. Like Ruskin, they live in pursuit of the innocent romance of creation—that moment when the colors were fresh, everything dried as it was meant to, and there was no thought of the hostile work of time. As Khandekar rightly observed, while many artists are reluctant to enter the interpretive fray when discussing their own art works, most are eager to discuss materials and the physical execution of their ideas.

Khandekar’s comment brought to mind the contemporary artist Michael Craig-Martin, whose drolly indirect meditations on art’s capacity to make you believe what you don’t see included “An Oak Tree” (actually a glass of water sitting on a high shelf), but who went on to develop a radical, almost violent chromophilia. At a time when conceptual art ruled, it took guts to claim that, in fact, color is concept, and perhaps the irreducible core of painting. For such theorists as Leon Battista Alberti, it was disegno (drawing), especially from classical exempla, rather than colore, that elevated art from artisanal craftsmanship to the noble visualization of humanist ideals. Such thinking persisted. Even the Cubists saw the emerging Henri Matisse, who had dissolved plane and line in a bath of flat color in such works as “The Red Studio,” as somehow disengaged from radical ideas.

A bottle of ultramarine blue made from lapis lazuli; Naples Yellow; a murex shell (in ancient times, ten thousand of the shells would be ground up to produce a gram of purple pigment); lead buckle, which was used for white pigment, although it eventually turns black; Lead-Tin Yellow, which was replaced by Naples Yellow when the new color was introduced, and later rediscovered.Photograph by Jason Fulford for The New Yorker

It is precisely the instinctive, demotic appeal of color that has sometimes led to its being discounted as mere showmanship. And the attempt to replicate optical vision with painterly practice in the name of being true to nature—the kind of advice Leonardo gave when he urged painters working in the open air to match paint samples to what they saw—has often been criticized as futile literalism.

But, throughout the history of art, and most evidently outside the West, color has carried with it a heavy freight of non-naturalistic value. Think of the iconic power of Byzantine mosaics, or the Gothic stained-glass and polychrome statuary that was offered as a vision of the heavenly Jerusalem. Color is social and moral, too. The colorman George Field, who opened the first of many factories of artists’ materials in 1808, near Bristol, England, considered his vocation to be the redemption of color from the murk of industrial obscurity—what he called “foul air.” He thought of himself as a reformer—manufacturing fresh reds, greens, and yellows to replace older, toxic pigments like cinnabar and orpiment. He inveighed against the poisonous horrors of Scheele’s, Paris, and Emerald Green, and championed viridian as a substitute, as if the ethical integrity of contemporary society were at stake; and, whenever science and industry supplied a new and safe color, he took it as providential. In 1856, William Perkin discovered the synthetic dye mauveine (Perkin’s Mauve), a purple that came from the residue of coal tar. Field responded in joyful terms to the transformation of the “black evil-smelling substance.” “At the touch of the fairy wand of science the waste land became a garden of tropic tints,” he wrote. “The world rubbed its eyes with astonishment and truly it seemed as wonderful to produce the colours of rainbow from a lump of coal, as to extract sunshine from cucumbers.”

In the late nineteenth century, the failed lay preacher Vincent van Gogh took the redemptive power of color-driven painting to a new extreme. Aided by the revelations of Japanese prints, his ecstatic illuminations were the result of chromatic calculations and inspirations, many of which are documented in his letters. Sadly, such experiments may have damaged his health. His “Self-Portrait Dedicated to Paul Gauguin,” from 1888, which hangs in the Fogg, has him posing against a turquoise-and-celadon-green background, which the artist described as “Veronese,” but which was, in fact, lethally toxic emerald green mixed with white.

Van Gogh—like William Morris and Kandinsky—believed that color acted directly on the soul. His Bible paintings, such as “The Good Samaritan,” from 1890, a variant on Delacroix’s composition, are usually regarded as sentimental embarrassments. But they arguably lie at the heart of his late œuvre, in which cypresses shake from some primordial upheaval and the firmament boils in the night skies of Provence. Van Gogh’s muscular stabs and dense ponds of paint were the antidote to academic art, requiring no need for visual tutorials: a rush of radiance for the masses toiling in their umbrous slog.

Gazing at Vincent posed against his poisoned teal, his jacket edged with the bright-blue trim of his imagination, I thought of the laborers behind all those Forbes pigments: the women who rinsed, kneaded, sieved, and dried the pulverized lapis lazuli that Giovanni Bellini used for the Virgin’s ultramarine robe; who stood waist-deep in horse manure, the vapors of which hastened the flaking of lead that produced the “lead white” used by Frans Hals and Rembrandt to capture folds of linen and lace. I thought of van Gogh claiming to recognize more than twenty black pigments in the portraiture of Frans Hals, the best of them created from charred bones. And of the bright pigments made in grim captivity: the North African slaves and the forzado convicts condemned to work in the mercury mines of Almaden so that the Spanish crown could sell cinnabar; the Caribbean slaves who grew and harvested indigo; the inmates of the Amsterdam House of Correction, rasping away at brazilwood.

And those gwalas in Mirzapur with their cattle fed on mango leaves—if indeed they existed at all. Toward the end of my visit to the Forbes, Khandekar, who has been following the ongoing debates surrounding Indian Yellow, waved a paper before me. “Guess what?” he said. According to two scholars at SUNY Buffalo State, in 1883 T. N. Mukharji sent samples of both purified and unrefined Indian Yellow to Kew Gardens, along with one of the earthenware collecting pots and a specimen of the cloths used to strain the urine before evaporation. In 2016, some of those samples, in addition to the balls of Indian Yellow from the Forbes Collection, were subjected to rigorous analysis using an array of novel techniques, including ultraviolet fluorescence and Raman spectroscopy. They were found to contain traces of the hippuric acid associated with animal, particularly ungulate, urine, and euxanthic acid—a possible by-product of the metabolic processing of mango leaves.

I have no idea why, on leaving Harvard’s palace of color, the vindication of Mukharji’s account should have made me cheerful. But I do know that you can order a synthetic version of Indian Yellow from the line launched by Bob Ross, the friendly TV painting tutor, for $7.29 a tube. Ross used it, just as Turner did, to “paint the sun in the sky.” ♦