Mr. Conrad grew up in Baltimore and Northern Virginia. At Harvard he majored in mathematics and was exposed to the radically unconventional musical ideas of John Cage and Karlheinz Stockhausen, both of whom lectured in Cambridge, Mass.

After his graduation in 1962, Mr. Conrad briefly worked as a computer programmer and immersed himself in New York’s experimental music scene. As part of Mr. Young’s ensemble, he performed seemingly improvisational pieces that involved holding notes for what might have felt like hours at a time. Some audiences found the music maddening; others were exalted.

“It appeared as if Schoenberg had destroyed music,” Mr. Conrad said in an interview with The Guardian in March, referring to the revolutionary Austrian composer. “Then it appeared as if Cage had destroyed Schoenberg. Our project was to destroy Cage.”

Mr. Conrad considered “The Flicker,” accompanied by a soundtrack of what he called “homemade electronic music,” to be an extension of ideas that he shared with Mr. Young. In a 1966 interview with the Village Voice critic Jonas Mekas, Mr. Conrad explained that he “was working within a form of light that is broken down not into areas or into colors but into frequencies.”

As austere as it was, “The Flicker” had the power to cause viewers to see color patterns, and even to induce hallucinations. Although there were some who did not consider “The Flicker” to be a film at all, it was included at the 1966 New York Film Festival. A photograph of a festival audience watching the film shows most people shielding their eyes or plugging their ears — and one spectator who seems transfixed.

In 1970, Anthology Film Archives, a center in New York for the preservation, study and exhibition of film and video, included “The Flicker” on its list of essential works of cinema art.