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Inside Harvard’s Incredible Collection of Rare Pigments | Conservation Lab

What’s behind art history’s most radiant hues? Sea snails, cow urine, and mummy flesh, apparently.
Image de Une : Les pigments de la collection Forbes viennent des quatre coins de la planète, certains sont même encore dans leur récipient d'origine. Photo : Jenny Stenger © President and Fellows of Harvard College.

In art institutions across the globe, time machines and investigation rooms exist behind closed doors. Dusty artworks go in and come out looking centuries younger; artists’ secrets are brought to light; and hidden, unfinished images emerge from behind famous compositions. Every week, we'll peek beneath the microscope and zoom in on the art of preservation, where art meets science and just a little bit of magic: this is Conservation Lab.


Behind glass walls, a long row of cabinets at the Straus Center for Conservation and Technical Studies exhibits a dazzling color spectrum of 2,500 hues. Walking alongside the extensive display of pigments, you’ll find brilliant purples turning into vivid reds, leading to yellows, then blues—which, in turn, guide you back to purple. As the color wheel unfolds, so does the rich history of paint production.

The Straus Center is part of the Harvard Art Museums in Cambridge, Massachusetts, and is the oldest such art conservation facility in the United States. Its pigment collection is crucial to researching and treating works of art. Ten years ago, for example, the Straus Center was able to identify that certain pigments used in three paintings attributed to Jackson Pollock were not available until after the artist’s death.

The materials collection, including the Forbes collection of pigments and the Gettens collection of media and varnishes, at the Straus Center for Conservation and Technical Studies, Harvard Art Museums. Photo: Zak Jensen, © President and Fellows of Harvard College.

In addition to the ever-growing pigment display—which contains the treasures amassed by Edward Waldo Forbes, an early director of Harvard’s Fogg Museum, as well as more modern samples—the Center’s materials collection also counts over 1,000 other objects, including binding media, historical scientific equipment, and minerals and stones dating back to antiquity.

Below, we unlock the cabinets with senior conservation scientist and Straus Center director Narayan Khandekar, and take a look at some of the most intriguing items.

All photos by Harvard Art Museums, © President and Fellows of Harvard College, unless otherwise noted

The collection includes this large rock of lapis lazuli from Afghanistan. “Ultramarine was created by mining the lapis lazuli stone from quarries in Badakshan (now Afghanistan) in the Middle Ages. It is still available as a pigment,” notes Khandekar. Natural ultramarine can be found in the Virgin’s mantle in Sandro Botticelli’s The Virgin and Child from 1490 (left), a tempera painting in the collection of Harvard’s Fogg Museum.


“Lead-tin yellow was used extensively until around 1750 and was not rediscovered until 1941,” cites Khandekar. The poisonous, lemon-colored pigment was frequently used by Vermeer in his draperies.

“Murex purple, also called Tyrian purple and red whelk, was used in Greek and Roman times for dyeing togas, and in the Middle Ages for decorating manuscripts,” explains Khandekar. The purple dye, made from a liquid secreted by mollusks found on Mediterranean shores and on the European Atlantic coast, fetched high prices, since production crawled along at a (sea) snail’s pace—no more than a single drop of colorant could be extracted from each animal.

Photo by Jennifer Aubin, © President and Fellows of Harvard College.

The above microsampler, which pairs a hypodermic needle and a microscope in order to collect tiny paint samples from works of art, was created in the 1930s by the Fogg Museum’s first scientist, Rutherford John Gettens.

At left, the rare pigment Zafferano di Aquila, made from “Aquila” saffron, a special variety of the highly sought after plant that is grown exclusively in Italy, and is known for its particularly intense color. At right, cadmium yellow, a toxic color used in Lego and other toys until the 1970s.

This pigment has one of the best names in the business: dragon’s blood. Its origins, disappointingly, are far from fantastical; the bright red resin is made from rattan palm trees.

Someone, at some point in history, thought, hey, here’s an idea—let’s make paint out of crushed up mummies. Mummy, or Egyptian Brown, peaked in usage during the 18th century, in British painting especially. The “raw materials,” however, were a hot commodity long before that, as mummy powder was believed to have all kinds of magical healing properties and were a mainstay in 16th century European apothecaries. “In the course of at least 300 years of trade, an unrecorded number of archaeological objects was destroyed in order to make pigment,” says Khandekar of the highly unethical practice, whose popularity finally petered out in the early 1900s.


Photo by Jennifer Aubin, © President and Fellows of Harvard College

Speaking of questionable practices, Indian yellow was originally made from the urine of cows fed exclusively on mango leaves.

The reddish pigment named carmine, above, is made from an acid that can be extracted from cochineal beetles. And it isn’t just used for art: it might be in your food and cosmetics, too.

The bright, alluring substance known as copper aceto-arsenite is a highly toxic powder that was once used to exterminate rats in Parisian sewers (hence its colloquial name, Paris green). As a pigment, it was prized by Impressionist and Post-Impressionist painters, including van Gogh. His 1888 Self-Portrait Dedicated to Paul Gauguin—another emerald green enthusiast—made ample use of the color, and is part of the Fogg Museum’s collection.

Photo by Jennifer Aubin, © President and Fellows of Harvard College

When it comes to bright hues from more contemporary times, these fluorescent pigments cry out for attention.

With so many materials worthy of note, it’s hard to know when to stop—but we’ll quit rummaging for now, and cue the fade to black.

Photo: Jenny Stenger, © President and Fellows of Harvard College.

To learn more about the Straus Center for Conservation and Technical Studies, go here.


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