In this file photo from April 11, 1956, Dorothy Dandridge is shown at her press reception at the Savoy Hotel in London. (THE ASSOCIATED PRESS, File)

NEW YORK - Dorothy Dandridge was the first black woman nominated for a Best Actress Oscar. Almost a half century passed before another black woman - Halle Berry - won the award.

They and three others - Pam Grier, Whoopi Goldberg and Oprah Winfrey - are subjects of the new book "Divas on Screen: Black Women in American Film."

"These women have pushed the racial boundaries for audiences, setting new standards for beauty and body type," said author Mia Mask.

She took on the book because, while black male stars are now enjoying huge success, little has been written about their female counterparts - as performers who can headline a film, said Mask, who teaches film and drama at Vassar College in Poughkeepsie, N.Y.

Dandridge was nominated for her lead role as the hedonistic factory worker in the 1954 classic "Carmen Jones," alongside Harry Belafonte.

Berry won an Oscar in 2000 for playing the wife of an executed murderer in "Monster's Ball." She also had portrayed Dandridge as a stunning femme fatale in a 1999 HBO film about Dandridge's life.

When Dandridge became a star, "she was working in an environment in which there were almost no women of colour (in leading roles)," said Mask, and Dandridge "had to fit into the mould of shapely and svelte."

By the time the statuesque Grier arrived on the Hollywood scene, she could break that mould with her forceful but hip physical presence as an action heroine.

As for Winfrey, Mask said she chose her because the talk-show host's television presence catapulted her film appearances to the level of global stardom, transcending any category.

In spite of vast changes, Mask said, sore points persist in casting black women for star roles: a paucity of quality parts, and a new trend of pairing black lead actors with female leads who are not.

"Studio heads don't think two black characters will appeal to general audiences," said Mask.

She chose Dandridge and Berry "as bookends" for the time span that transformed black women in commercial films.

"We've gone from the trope of the tragic mulatta to biracial beauty," said Mask, who is taping a five-part series for National Public Radio to air in late October - each on one of the women in the book.