How Harold Edgerton’s ‘Bullet through Apple’ made time stand still

By Waseem Akram On Jan 6, 2023

Written by Oscar Holland, CNN

In Snap, we look at the power of a single photo, telling stories about how modern and historical images were made.

Bursting with energy but still perfect, Harold “Doc” Edgerton’s 1964 image of a .30-caliber bullet tearing through an apple showed a moment that could not be seen in captivating detail. The scene took on a calm, sculpted beauty as the apple’s crumbling skin exploded against a deep blue background.

The picture is widely regarded as a work of art. More important to its creator, however, it was also a feat of electrical engineering. The longtime professor at the Massachusetts Institute of Technology (MIT) used it to illustrate a lecture, famously titled “How to make applesauce,” in which he explained the innovative flash technology that helped him take a picture.

Edgerton, who died in 1990 aged 86, is considered the father of high-speed photography. The camera shutter speed was too slow to capture a bullet flying at 2,800 feet per second, but his stroboscopic flashes – the precursor to today’s strobe lights – created bursts of light so brief that a photograph with a good time to raise in an otherwise dark room. , appeared as if time had stood still. The results were surprising and, often, misleading.

“We used to joke that it took a third of a microsecond (millionth of a second) to take the picture – and all morning to clean up,” recalled his former student and teaching assistant, J .Kim Vandiver, on a video call from Massachusetts.

The 1964 image has become one of the most famous photographs of the 20th century. Credit: Harold Edgerton/MIT; courtesy of Palm Press

While early camera operators had experimented with pyrotechnic “flash powders” that combined metallic fuels and oxidizing agents to produce a brief, bright chemical reaction, Nebraska-born Edgerton invented flash which was much shorter and easier to control. His breakthrough was more a matter of physics than chemistry: After arriving at MIT in the 1920s, he developed a flashtube filled with xenon gas that would cause electricity to jump between two electrodes for a fraction of a second when under high voltage. .

By the time he fired the shutter for the now famous apple photo, Edgerton had developed a microflash that used clear air instead of xenon. He also produced decades worth of famous photographs: hummingbirds in mid-flight, golf clubs hitting balls and even nuclear bomb explosions. (During World War II, Edgerton developed a special “rapatronic” – or rapid electronic – camera for the Atomic Energy Commission that could control the amount of light entering the camera during the explosion.)

However, it was his bullet photos from the 1960s that proved some of the most memorable. According to Vandiver, who still works at MIT as a professor of mechanical engineering, the challenge was not getting the flash out but turning off the camera at the right time. Human perception was too slow to take the picture by hand, so Edgerton used the sound of the bullet itself as inspiration.

“A microphone would be out of the picture, right below,” Vandiver said. “So when the shock wave from the bullet hit the microphone, the microphone would trip the flash and then you’d close the (together after that).”

Image making

Over the years, Edgerton and his students have rifled through objects including bananas, balloons and playing cards. For Vandiver, the reason the apple – along with the 1957 image of a splashing milk drop – became one of Edgerton’s signature images is, in part, its simplicity. “It captures your imagination… and you immediately understand what it is,” he said.

Another of Edgerton’s famous photographs, taken in 1957, shows the crown-like spray created by drops of milk. Credit: Harold Edgerton/MIT; courtesy of Palm Press

Another factor was at play: Edgerton’s artistic eye. The beauty of his images led to reprints in newspapers and magazines around the world, and more than 100 of his paintings are housed at the Smithsonian American Art Museum today. But Edgerton declined the additional title.

“Don’t make me out to be an artist,” he has said. “I’m an engineer. I’m after the truth, just the facts.”

Although Vandiver said “there is certainly an artistic legacy” to Edgerton’s visual experiments, which advanced the field of photography, his research also had a profound impact on science and industry. His hands-on approach lives on at MIT’s Edgerton Center, which was established in his honor in 1992. Vandiver, who is the center’s director, said all students are encouraged take shots of themselves.

“We still teach the course, and students still come up with weird things to take pictures of,” he said, recalling recent images of colored chalk and lipstick torn by bullets. “The apples are tired now.”