Supermodel Naomi Campbell glittered as the grand finale to Diane von Furstenberg's show at this week's New York Fashion Week, but DVF is the exception to what Campbell and others are calling racism on the runway.

"I don't like it, and I say it," Campbell, 43, told ABC News. "I say, 'Where's the others?' I'm very outspoken, as we know."

Now, as part of an advocacy group called "Diversity Coalition," Campbell, beauty icon Iman and former model-turned-advocate Bethann Hardison are taking the unprecedented step of naming high-profile designer names who they say are sending a negative message by appearing to define beauty and high fashion as virtually all white.

In an open letter to the governing bodies of fashion weeks across the globe, based on what they saw at last season's fall shows, Campbell, Iman and Hardison name designers Calvin Klein, Donna Karan, Armani and others for using just "one or no models of color" in the fall shows, which featured dozens of models, calling it a "racist act."

"The statistics, it's really shocking," Campbell said. "Heartbreaking. Your body and beauty, it doesn't matter what color you are. If you've got the right talent, you should be there having the opportunity to do the job."

They hope that by speaking out, diversity will become fashionable. "Who else? Iman asked. "Who's going to do it [speak out]? Somebody has got to do it. And change does not happen easily."

Hardison said, "I don't want to try and embarrass anyone to do anything."

"You know, this is not the business of shaming," Iman, 58, agreed. "And as we go back again to clarify it, nobody is calling any of these designers racist. The act itself is racism."

Iman, the supermodel turned makeup mogul, also known as Mrs. David Bowie, may be a mega power player, but she says she's outraged that things haven't changed since the 1970s.

"There were more black models working then than it is happening in 2013," she said. "There is a time when silence is not acceptable at all. And if the conversation cannot be had publicly in our industry, then inherently there is something wrong with the industry."

ABC News reached out to many of the designers on the list and none responded to requests for comment.

But Campbell praised Diane von Furstenberg and other designers for taking diversity seriously. She said Tom Ford casts all his own runway models and doesn't rely on casting agents or "stylists" to make that judgment. "He has diversity because he sees the beauty in diversity," Iman said.

The Council of Fashion Designers of America sent two emails to the designers in New York Fashion Week, writing, "The most powerful message is one of diversity," it told ABC News.

But industry analysts say the excuse is often artistic.

"As a creative visionary, people do have very specific, artistic notions of how they want all their creations to be presented," said Emma Rosenblum, the Etc. section editor at Bloomberg Businessweek.

Campbell's not buying it, saying, "I think they hide behind aesthetics."

Added Hardison, who broke barriers along with Iman in the 1970s: "I think they're ignorant and they're arrogant, and I think it's not even about racism.

"I think it's a sense of laziness and they've told themselves a story."