Hope you had a good weekend. Thank you all for the kind notes about Friday’s newsletter — I really appreciate it! — Dan

How Bad Film Captured an Explosion

On August 6, 1945, the United States detonated an atomic bomb over the Japanese city of Hiroshima. Three days later, the U.S. dropped a second such bomb on Nagasaki, effectively ending World War II. This was the culmination of the work done by the Manhattan Project, the American undertaking to be the first nation in the world to develop such a weapon.

To get to that point required a lot of testing, and for obvious reasons, the government wanted those tests to be kept as secret as possible. For example, on July 16, 1945, the Manhattan Project detonated a plutonium bomb at the Alamogordo Bombing and Gunnery Range in New Mexico, about 125 miles (200 km) south of Albuquerque. (Here’s a map.) The test, known as “Trinity,” was detectable by civilians miles away, and the government needed to account for this. The solution: a cover story. The commanding officer of the base told the local newspaper that “a remotely located communication magazine containing a considerable amount of high explosive and pyrotechnics exploded,” and the newspaper thought so little of the whole thing that they buried the story on page 6.

But someone did notice the nuclear bomb tests — someone in Rochester, New York, nearly 2,000 miles away.

Since 1888, Rochester has been the headquarters of The Eastman Kodak Company, a pioneer in film and photography products. One of their products was film for X-ray machines. In the late summer and fall of 1945, customers of that film began to complain to Kodak; as Photography Talk reported, “the radiosensitive film was coming out completely foggy” and therefore, useless. Kodak was at a loss as to why — the X-ray film customers complained about went through the exact same production, storage, and shipping process as previous batches, and that process was already fine tuned to prevent contamination from radium and other radioactive elements that could cause fogging. They got to work looking for an explanation. A physicist in their research department named Julian H. Webb took it upon himself to investigate some of the bad film, and he discovered something odd.

Webb tracked the problem down to strawboard that Kodak produced at a mill in Indiana, a far cry from both Rochester and New Mexico alike. The strawboard was placed between sheets of the X-ray film to keep them from scratching or otherwise damaging each other, but in this case, the strawboard caused the damage. The reason? The strawboard contained something that shouldn’t have been there: a radioactive isotope called Cerium-141 that didn’t exist anywhere in nature.

As SciShow explains, that seemed similarly impossible: “Since the raw materials in the mill were stored indoors and away from any source of radioactivity, Webb knew that couldn’t be the problem.” The most likely explanation was the water being used to treat the materials, which was coming from a nearby river. When Webb tested the water, he found Cerium-141. But the radioactive isotope wasn’t coming from some sort of upstream contamination. Per Popular Mechanics, “additional evidence would fall in the rain. According to Webb, ‘stronger activity occurred in the strawboard’ after periods of heavy precipitation, establishing that the radioactive material was being deposited via precipitation and came from a far-flung place.”

That far-flung place turned out to be the New Mexico desert. There’s no reason to believe that Webb could pinpoint that, but it wasn’t hard for him to figure out the general idea of what was going on. Because of the bombs dropped on Japan, he (and everyone else) knew about atomic bombs; it only made sense that the U.S. was testing them and that those tests could result in rainwater contaminated with radioactive isotopes.

Webb ended up sharing his findings in a paper in 1949 but no one seemed to really care — above-ground nuclear tests continued into the early 1960s. But during that interim decade or so, the tests caused a problem for Kodak. While the dangers of fallout from nuclear explosions were not very well known generally, Kodak understood the specific harm that it could cause to film. In 1951, Kodak threatened to sue the government for the damage these bombs were causing to its business, and the two sides settled. The U.S. government provided Kodak with the details about its future tests, giving the company enough information to keep its film safe. Kodak, in return, dropped the threat of a lawsuit — and also agreed to keep the information the government provided a secret.

Today’s Bonus fact: While Webb probably didn’t figure out where the U.S. government ran the Trinity test, another civilian likely did. John W. Campbell was the editor of a magazine titled “Astounding Science Fiction” from 1937 until his death in 1971. In 1944, he green-lit a story idea by writer Cleve Cartmill about an extraordinarily powerful bomb, and then gave Cartmill ideas for some details that could be included. Those details came from unclassified scientific journals, and included mention of Uranium-235, the isotope used in the real atomic bombs being built. Cartmill ended up including the details in his story, titled Deadline, which you can read here. When the FBI got wind of the story, they investigated, concerned that someone had been leaking information about the super-secret Manhattan Project.

The investigation discovered that this was a mere coincidence, and, per Wikipedia’s editors, “The FBI descended on Campbell's office after the story appeared in print and demanded that the issue be removed from the newsstands. Campbell convinced them that by removing the magazine ‘the FBI would be advertising to everyone that such a project existed and was aimed at developing nuclear weapons’ and the demand was dropped.” But Campbell himself now had a lot more information than the FBI intended. Not only did he know that the article had come dangerously close to reflecting reality, but he also had the list of addresses that had ordered copies of “Astounding Science Fiction.” A lot of homes near Alamogordo were newly on that list.

From the Archives: Nuclear Photographs: Why Kodak built a secret-ish nuclear reactor of their very own.