Corinne Day, whose frank, unadorned photos of a teenage Kate Moss in the early 1990s helped inaugurate a new era of gritty realism in fashion photography that came to be called “grunge,” died Friday at her home in Denham, a village in Buckinghamshire, England.

The cause was a cancerous brain tumor, said her agent, Susan Babchick. According to her website, Day was 45, but public records indicate she was 48.

Day’s passion to record the most profound human experiences with a camera was never more evident than the day in 1996 when the tumor was discovered after she had collapsed in New York. She promptly asked her husband to shoot pictures of her, and they continued the project through her treatment and decline.

“Photography is getting as close as you can to real life,” she said, “showing us things we don’t normally see. These are people’s most intimate moments, and sometimes intimacy is sad.”

Day built her reputation on unrelenting visual honesty. She refused to airbrush the bags from under models’ eyes or de-emphasize their knobby knees. She eschewed pretty locations or even studios in favor of shooting people in their own environments.

It added up to a startling detour from the glossy world of supermodels — “subversion,” in Day’s own phrase.

There were two defining moments along the way, both involving Moss. The first was in 1990, when some of the first published fashion photographs of Moss, taken by Day, appeared in the British magazine The Face. One showed Moss topless; another suggested she was naked. She wore a mix of designer and secondhand clothes and no makeup over her freckles, and her expression was sincere. The photos seemed to usher in a new age of anti-fashion style. Artlessness became art. Some called it “grunge.”

The second moment, in 1993, was a shoot for British Vogue that featured a pale and skinny Moss in mismatched underwear. A public outcry ensued, as some claimed that Moss’ waifish figure seemed to imply she was suffering from an eating disorder or drug addiction.

On her agent’s advice, Moss stopped working with Day, with whom she had become close friends. Day said she was tired of taking fashion pictures, anyway.

“I think fashion magazines are horrible,” she said in an interview with the British newspaper The Observer in 1995. “They’re stale and they say the same thing year in and year out.”