American Newspaper Repository Collection, Duke University (The World, New-York Tribune, The Chicago Sunday Tribune); The Forward Association; The New York Times

Why did the Triangle fire embed itself so firmly in the popular conscience, while other disasters — equally cruel, equally preventable — disappeared into the fog of civic amnesia?

Union organizers usually get much of the credit for having kept the event alive as a landmark in the fight for occupational safety and fair labor practices. But their efforts were aided immeasurably by the existence in 1911 of a growing photojournalism corps, ever-improving printing technology and a public hungry for images.

“It’s certain that press coverage of the fire, and especially its gruesome aftermath, contributed to a movement to enact workplace safety laws,” said Michael L. Carlebach, a professor at the University of Miami and the author of “American Photojournalism Comes of Age” (Smithsonian Institution Press, 1997). “It also energized the unions, enhancing the membership and power of, among others, the International Ladies’ Garment Workers’ Union.”

The pictures and accompanying news stories offered irrefutable proof of the need for reform at the same time that they corroborated what union leaders and Progressives had been saying for a decade or so. The power of the pictures seemed to end the debate and do so on the side of the women and their union. Therein lies the power of photographs on the printed page.

Within 24 hours of the fire, candidly brutal pictures of the tragedy were in circulation — by the hundreds of thousands. Within 48 hours, readers primed by the sight of broken bodies on the streets near Washington Square and Grace Church could visit the gutted interior of the crucible itself to see pictures of a locked stairway gate.

In its sheer scope, coverage of the Triangle fire was one of the earliest such graphic, public, inescapable and almost instantaneous media assaults on genteel sensibility. And the basic formula — awful event one day, photos published the next — still holds a century later.

“Seeing a gruesome photo in the newspaper of a fallen body — the realism of that is unexpected and staggering,” said Andie Tucher, an associate professor in the Columbia University Graduate School of Journalism. “It’s not even that it’s done so fast, but that it’s done in so public a way.”

100 Years Later The 1911 Triangle Fire Remembering the fire that killed 146 workers at a garment factory in Manhattan and its lasting impact. Read Complete Coverage »

She contrasted Triangle coverage with a photojournalistic tradition going back to the Civil War, in which pictures of news events were seen weeks or months later in magazines, at galleries or on postcards and cabinet cards — that is, under limited or controlled circumstances.

Pictures of the Triangle fire were available the next day, all around the city, to anyone who could spare a nickel for a Sunday paper or just glanced in a newsboy’s direction.

Alison Nordstrom, the curator of photographs at George Eastman House in Rochester, said the mere existence of the photos was not in itself sensational. “By 1911, people expected to get their news visually,” she said. “The yellow press had established the use of screamer headlines and lavish illustrations by 1895.”

“Most people were well aware of the abuses of the sweatshop,” Dr. Nordstrom added. “What this event and the photographs of it did was put a face on those facts.”

Joseph Pulitzer’s World, and The New York Herald, owned by James Gordon Bennett Jr., led the way. The front pages of these broadsheets were given over to news photos from the scene. The Herald’s leading picture, from a few feet away, showed bodies akimbo on the glass lights of a cast-iron sidewalk vault. It is still painful to behold.

American Press Association

The photographer for The World stood back a few more yards, but there was no mistaking the image as anything but corpses littering a sidewalk. The New-York Tribune also had a front-page picture of fallen bodies, though it treated the image more like an illustration, mortising it into a drawing and letting the retouchers obliterate its details.

Significantly, even the sensation-averse Times ran a front-page photo of the fire, though it was a far more circumspect view than those in the competition. (It showed the exterior of the burning building as seen from down the block.) The inside pages, however, carried photos nearly as graphic as those in The World — about the last paper in the world that Adolph S. Ochs, The Times’s publisher, would have cared to emulate.

Photojournalism had clearly come of age if it was playing such an important role in the Gray Lady.

In 1880, The New York Daily Graphic had been the first newspaper to print a halftone engraving, composed of a field of countless dots whose varying size could render a range of gray tones. The first halftone photographs in The Times — two historical portraits — appeared in its illustrated Sunday magazine in 1896. A year later, Stephen H. Horgan, who had introduced the halftone method at The Graphic, further perfected it at The Tribune so that halftones could be run on high-speed rotary presses.

The Graflex camera, introduced by William H. Folmer in 1902, had evolved into the Press Graflex, the most popular newspaper camera at the time of the Triangle fire, said Todd Gustavson, the curator of technology at George Eastman House. Among the many important attributes of the Press Graflex was that it could be hand-held.

For all these advances, however, The Times appeared to be in no hurry to showcase photography in its news pages. Through all of 1909, there wasn’t a single illustration on Page 1, except for a map of the North Pole. The first front-page photograph, showing the aviator Glenn H. Curtiss taking off from Albany on a flight to New York, did not appear until May 1910.

American Press Association

In August 1910, The Times had a chance to print a startling close-up photo of the bloodied Mayor William J. Gaynor, moments after he’d been shot by a former city employee. The editors declined to “front” it. Instead, they gave the place of honor, directly under the main headline about the assassination attempt, to a formal portrait of Gaynor by Underwood & Underwood.

The more dramatic picture, which ran on Page 2, was taken by Wade Mountford Jr. of the American Press Association, a syndicate founded in 1882 by Maj. Orlando Jay Smith. (Its headquarters still stands, and its name can still be seen, at 225 West 39th Street.)

The American Press Association also furnished The Times and The Tribune with many of the pictures they printed of the Triangle fire. Though none of the individual photographers were credited, Mr. Carlebach can’t help but believe Mr. Mountford would have been among them.

It is, of course, possible to overstate the importance of the pictures. “There were no actual photos of the Titanic sinking into the ocean in 1912,” said Ann Rauscher, the exhibits editor at the Newseum in Washington, “yet the press coverage of the disaster and the massive loss of life resulted in safety reforms such as requiring ships to have enough lifeboats for all passengers.”

Hal Buell, the retired director of photography at The Associated Press, who has written about the history of photojournalism, said he believed he could say for certain what kind of impact the Triangle fire pictures would have today.

“These pictures would inspire considerable comment,” Mr. Buell said, “most of it negative, from readers who would cite insensitivity, invasion of privacy, titillation and other antimedia issues. That virtually always happens with tough pictures today.”