Quest for Permanence

The New York Public Library was one of the buildings protected by Toch Brothers’ paints. (New York Public Library)

The New York Public Library was one of the buildings protected by Toch Brothers’ paints. (New York Public Library)

A “Chemist’s Notion” of Art Authentication

Just as Toch’s work on the permanence of naval paint was his entrée into the world of military camouflage, his investigations into the permanence of art paint led him to the science of authentication. And while Toch felt that he never received the public credit he deserved for his military work, his work in analyzing paintings put his name on the front page of the New York Times. His new interests also embroiled him in a feud no less heated than the regulatory hearings of two decades before.

Toch first spoke publicly about his work in authenticating art in 1914, at a lecture he gave at Philadelphia’s Franklin Institute. At the request of an apprehensive collector Toch had carefully examined a painting purported to be a 1650 work by the Dutch landscape painter Jacob van Ruysdael. Art critics suspected forgery but had no solid proof. Toch used photomicrograph techniques from his industrial paint research to uncover details of the painting’s brushwork. He also removed a minuscule portion of paint for microscale chemical analysis. The latter test revealed zinc oxide, a pigment not used until the 19th century. Faced with this evidence, the art dealer offering the painting confessed.

After the war Toch took up a new tool for authentication: X-rays. Scientists began to probe paintings with these new rays very soon after they were discovered in 1895, but patent protection and World War I halted the early investigations. After the war Toch took to making X-ray photographs, or “shadowgraphs,” of paint samples and paintings. Thicker coats of pigments and those made up of heavy elements (such as lead) absorbed a greater proportion of the X-rays and left the portions of film directly behind these areas less exposed. Just as medical X-rays displayed the structure of the body underneath the skin, Toch’s shadowgraphs revealed earlier “drafts” of a work hidden from the naked eye behind changes made by the original artist or by restorers. Toch put both photomicrographs and the X-ray to use in his best-known authentication effort. In 1923 Rutgers University art historian John van Dyke enlisted Toch in support of a sensational claim—that most of the paintings around the world attributed to Rembrandt (including the 15 or so in the collections of New York’s Metropolitan Museum of Art) were the work of his students or followers. Toch took photographs of the painting “Old Woman Cutting Her Nails” through different filters to highlight certain portions of the painting. Van Dyke used these images to argue that the painting’s design, shading, and brush strokes differentiated it from Rembrandt’s style and linked it to another painting positively attributed to Rembrandt’s pupil Nicolas Maes. But the majority of Rembrandt historians, including the Met’s curatorial staff, were not persuaded.

In 1931 Toch took this argument to the American Museum of Natural History. In a lecture there before the New York Microscopical Society, Toch revived Van Dyke’s claim. The chemist was slightly more generous than his art historian ally: of the Met’s 27 paintings attributed to Rembrandt (the collection had grown), Toch allowed one genuine Rembrandt. Chemical analysis revealed no anachronistic pigments in the paintings, but Toch claimed that his X-rays and photomicrographs revealed brush strokes entirely unlike Rembrandt’s.

The New York Times immediately picked up the story; other newspapers followed. William Valentiner, the foremost Rembrandt expert in the United States and the author of a new book certifying the Met’s paintings as the master’s genuine work, vehemently rejected Toch’s claim. The chemist “as little deserves being noticed as Herostratus, who set fire to the Temple of Ephesus in order to become famous,” Valentiner fumed.

Toch responded angrily, lambasting “old-fashioned” art experts for authentications based on subjective judgments. “The way of judging a painting by squinting at it with a half-closed eye and then writing a long dissertation, known as a certificate,” he wrote, could not long survive when pitted against modern, scientific methods. In newspaper interviews and articles spread over several years Toch continued to advocate for technological alternatives, such as ultraviolet and infrared photography. Lay observers, however, were more confused than galvanized. A Baltimore Sun editorialist dismissed Toch’s assumption of consistency in each artist’s brushwork, a crucial element of his authentication arguments, as “a chemist’s notion of how a painter works.”

By the mid-1930s Toch had lost the attention of journalists and with it his public forum. He died in 1946 knowing that his Rembrandt claims had been rejected. History, however, rendered a judgment of Solomon. Since Toch’s death about half of the paintings he challenged, including all three singled out in his 1931 lecture—“Old Woman Cutting Her Nails,” “Pilate Washing His Hands,” and “The Artist’s Son Titus”—have been reattributed to followers of Rembrandt.

Toch dedicated his life to ensuring the reliability of materials in a modern, urban world that both demanded permanence and threatened that permanence with pollution, war, and plain old wear and tear. Ironically, Toch’s own legacy has proven fleeting. He is remembered as a minor figure in American industrial chemistry and as the author of minor handbooks on artists’ paints. Yet Toch and his paints served as guarantors of the permanence of the modern world of steel and concrete, staving off decay and destruction and carefully preserving the integrity of a much older cultural legacy.

Evan Hepler-Smith is a doctoral candidate in the Program in History of Science at Princeton University. His dissertation will address the history of systematic nomenclature in organic chemistry.

Augustin Cerveaux was the 2007–2008 Ullyot Scholar and the 2011–2012 Cain Fellow at CHF’s Beckman Center.