Beginning at New York's Fashion Week earlier this month, Ms. Hardison was organizing a social media campaign to bring public scrutiny to designers who did not use black models.

James Scully, a casting director whose clients include Tom Ford, Derek Lam and Stella McCartney, went public in March with a scathing critique of shows that did not reflect a diverse casting, naming Dior, Saint Laurent, Louis Vuitton and Chanel.

"I feel the Dior cast is just so pointedly white that it feels deliberate," he said in a BuzzFeed article.

In July, when Mr. Simons presented his couture collection for Dior, the show included six black models, prompting speculation that the change came in response to Mr. Scully's remarks. That week, Prada released a campaign featuring Malaika Firth, the first black model to appear in its women's advertising in nearly two decades.

Representatives for both labels refused to discuss the subject.

Calvin Klein, once a vastly diverse show, has been faulted for its mostly white casting.

At the New York show this month, there were signs that the recent pressure could bring changes. There were five black models in the 35-look Calvin Klein show on the final day. But over all the changes were small: more than half the designers who were faulted last season used two or more black models this season, but it was only two for the majority of them. And many people noticed that there were no Asian models at the show.

Francisco Costa, the women's creative director, said in an e-mail that the company looks for diverse faces in its casting. But, he wrote: "There are only a handful of top-level, professionally trained models of color at a particular level out there now, and they end up being booked by other fashion houses and can be seen on dozens of runways each season, which is counter to what we are looking for."

Riccardo Tisci, the Givenchy designer, who has been heralded for representing a range of races, ages and genders, says those who cast only white models do so out of "laziness."

"There are not only white people around the world," he said.

Veronica Webb, who encountered excuses when she walked the runways in the'90s, said the issue is an important one for young women.

"When you see someone that looks like you," Ms. Webb said, "it makes women feel beautiful, and it makes women feel they belong."

The New York Times

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