Baz Luhrmann’s “The Great Gatsby” has the straw boater hats and bowties, the cloches and drop-waist dresses, and the shiny roadsters that you’d expect of the Roaring Twenties. But in terms of women’s fashion, there’s one dominant element you would not expect: Boobs.

“People would be startled if filmmakers put real 1922 fashion in ‘The Great Gatsby.'”

Breasts are everywhere in 2013’s new “Gatsby,” which came out on DVD last month. They’re pushed up to create cleavage, peeping out of frocks and fringed flapper dresses, and hugged tightly by clothes cut to show off curves. As Daisy Buchanan, Carey Mulligan is clearly wearing some sort of shapewear or bra under even her most modest clothes, to make her breasts seem perfectly perky.

Catherine Martin, the producer, production designer, and costume designer of “The Great Gatsby,” says that she simply took the styles of the 1920s and amped up the sexy quotient—and made the dresses fit more like the designers intended.

“If you look at the fashion illustrations, as opposed to what actually ended up being made, you will see that the ’20s were all about sex,” Martin tells Collectors Weekly over the phone. “It was the first time that women basically wore no undergarments and not even a [garter] belt. There were a lot of backless dresses, a lot of deep Vs. And you’re very conscious of the nakedness of people under the clothes.”

While all of that is true, boobs were not at all front and center in the 1920s. Just take a look at the site for the Gatsby Summer Afternoon in Oakland, California, an event that attempts to accurately re-create a high-society picnic from the era between the world wars. There’s a “How to Gatsby” guide, that details the changes in 1920s fashion, stating, “While the skirts had many shapes, the torso remained flat-chested throughout the decade.”

The new “Gatsby’s” emphasis on breasts is “the place where modern sensibilities made their way in,” says Alice Jurow, board secretary and office administrator of the Art Deco Society of California, which puts on the Gatsby Summer Afternoon. She says she loved the movie, which is probably a minority opinion among the society, as most members prefer more period-perfect films. “I don’t think Baz Luhrmann was trying to do a period piece, so I’m giving the filmmakers a pass on that. But flaunting cleavage was not the look. In the 1920s, there was definitely a flat-chested ideal, and it was fashionable to have your clothes fit very loosely and slither around you, which was its own kind of sexiness without showing off the exact lines.

“Definitely not everybody’s figure would lend itself to the androgynous look,” she continues. “It was an ideal, though, for very young, trendy, fashion-conscious women even to the extent of wearing ties and other masculine details and, of course, the little boy haircuts. It was thought of partly as boyish and androgynous but also as youthful.”

These new styles were an explicit rebellion against the constraining Victorian and Edwardian fashions of previous decades, when women used corsets to push their breasts upward and outward and pinch their waists down into hourglass shapes. Jonathan Walford, co-founder of the Fashion History Museum, says the Roaring Twenties party scene viewed the release of women’s bodies from constraining undergarments as wildly sexy.

“Dresses featured legs, arms, hips and faces, not cleavage,” Walford writes in an email. “It meant a woman was no longer bound by convention—she was liberated from the confines of traditional femininity because she could think for herself, dance and drink and smoke and swear, and that is sex appeal.”

For the body-hugging fit of the film’s clothes, Martin, who is also married to “Great Gatsby” director Baz Luhrmann, says she took inspiration from a recent exhibition of the clothes designed by 1920s innovator Jeanne Lanvin at the Museé des Arts Decoratifs in Paris.

“It was interesting to see clothes in person, styled on a mannequin, and then see a model of the period in the same clothing, in a black-and-white photo,” she says. “I noticed how ethereal and extraordinary the clothes seemed on these very neutral dummies and how incredibly frumpy the clothes looked on the person wearing them in the photograph.

“I think that what we understand as a ’20s silhouette is very much from the snapshot or from the social pages,” she continues. “But when you see the sketch of the creator, there is a big disconnect. What we chose to do, because we wanted to really capture the spirit of the ’20s, is really look at a lot of illustrations that people drew of the clothes.”

In other words, Martin’s movie is more about the fantasy world of the 1920s in the minds of forward-thinking designers, and not how it looked in real life. And she believes the ’20s ideas about sex appeal were much closer to 2013’s. But to Walford, it’s more like Martin imposed modern reality-TV standards of beauty onto “Gatsby,” which was set during a time when people admired an entirely different aesthetic.

“Frankly, I am a bit shocked by Martin’s quotes regarding the 1920s—that she considers the clothes frumpy looking,” Walford says. “She was the wrong costumer to get the job if she can’t see the beauty in the real 1920s silhouette. We just happen to be in an era where the trappings of femininity are back in style—cleavage, big butts, and curvy long legs. Look at television: The ‘Real Housewives’ shows are all about the artificiality of femininity.”

“If you look at the fashion illustrations, you will see that the ’20s were all about sex.”

Instead of rigidly adhering to the book’s timeframe (F. Scott Fitzgerald’s classic was published in 1925 but set in 1922), Martin took looks from all over the decade. In the movie, Jordan Baker, played by Elizabeth Debicki, sports a pantsuit, a look that wasn’t remotely acceptable until the end of the decade, and later she wears bejeweled halter dress that was on the cutting edge of fashion. Daisy Buchanan first appears in a strapless, natural-waist white gown, with a big feathered skirt nearly reaching the floor. Was this what an old-fashioned girl might wear in the 1920s? No, it’s really too racy for Edwardians—more of a feminine 1930s Hollywood look.

“Catherine Martin also picked up on some obscure designs that were not popular fashions in their day but rather fantasy designs, like those by Erté whose fashion sketches were intended for magazine covers and chocolate box lids and were never made into garments,” Walford says.

“For example, there were one-shouldered and halter top dresses designed in the 1920s, but good luck finding more than one or two references to them in period magazines—I believe I have seen one of each in museum collections. It would be a bit like setting a movie in 2010, and dressing the cast in Alexander McQueen runway couture. That’s fine if you are creating a fantasy film, but not if you are trying to re-create the period because McQueen runway couture was not worn by anybody other than Lady Gaga and Daphne Guinness—hardly your average fashion.”

Many argue that this “Great Gatsby” is meant to convey how the changes in 1920s would feel to us; jazz music would be as edgy as hip-hop, for example, and cleavage telegraphs sexual availability in the way that exposed ankles and knees used to.

“The whole thing was highly stylized, and I thought that was appropriate because Fitzgerald’s prose is often highly stylized,” Jurow says. “‘The Great Gatsby’ explicitly is set in 1922, but I don’t think there has ever been a filmed version of it that adheres to that specific moment. The very first movie, the 1926 silent film, we can only find a trailer and maybe a few stills, but the fashions that you see are mid-’20s. They were just telling it as a modern story.

“When people say ‘the Gatsby era,’ there’s definitely a mid-’20s concept that comes to mind, with the shorter skirts and the real archetypal flapper look. But 1922, it was the Jazz Age in terms of music, but the fashions hadn’t quite caught up yet. The skirts were still mid-calf, even approaching ankle length. Clothes were a little more graceful and ornate and flowy. People would be startled and disturbed if anybody actually did real 1922 fashion in the production of ‘Great Gatsby.’ It’s just not how we picture those characters.”

Given that most “Gatsby” films feature post-1925 looks, Jurow says she thought the clothes were pitch perfect for each individual character described in the book.

“They served the characters well,” Jurow says. “For instance, all of Jordan Baker’s outfits were almost spot-on, especially her daywear, perfect 1926-ish styles. Daisy’s clothes were not exactly like anything that I’ve ever seen in a historical context, but they reinforced her character also. Given that she was very, very rich and could have whatever she felt like, she might have felt like being encrusted with pearls. I liked the slightly more flashy and vulgar looks that Myrtle Wilson and her friends had, with the brighter colors and the slightly tighter fit.”

Along with expressing the spirits of the characters, Martin says she was also intent on capturing the shock value of the decade. “If you look at Paul Poiret’s strapless feather dress that he designed for his wife and you see the sketch, the skirt is voluminous, and the contrast between the slim torso and the volume of the feathers is huge,” Martin says. “Then you cut to a photo of Mrs. Poiret in the dress. And somehow the drama is not there anymore to the same degree. And I think what we chose to do was to take that spirit and make sure that the drama was still in the clothes.”

For Walford, that’s a betrayal of the period. “Fashion sketches are idealized: They show women that, in reality, would be 7 feet tall with size 3 shoes,” he says. “Her argument is a bit like saying the ideal female figure is the same as Barbie, which in one way it is, but it’s not authentic or realistic.“

Martin says that Erté and Lanvin led the way for more body-hugging style, experimenting with bias-cut designs in the 1920s, and that the popularity of film led women to realize how unflattering loose-fitting designs were, when they could see them from many angles.

“It is true that Madeleine Vionnet’s clothes were more body conscious at the very end of the 1920s,” Walford says. “But her clothes were the exception to the fashion and led the way into the 1930s style, which was more body conscious. None of Vionnet’s dresses were tight-fitting, but they did compliment the female silhouette by hugging the hips in bias-cut velvets and crepes. However, her clothes were not influential until the eve of the Depression.”

For Martin, the 1920s were all about women defining sexuality for themselves. “When you think of the ’20s, you think of Jeanne Lanvin, you think of Coco Chanel, you think of the Callot sisters, you think of all these women who are making clothes for their contemporaries,” she says. “It’s really the birth of the female fashion designer. That was very new thing. And it’s about a conversation that women are having with other women about who they are, what’s appropriate to wear, what is fashion, what is appropriate for my active life as a working woman.”

It was also the first time in the 20th century that young people dominated American culture, openly rejecting the ways of previous generations, who’d brought them into World War I. It seemed that everyone wanted to shake off the horrors of war and go back to a time of child-like innocence and frivolity.

“During the 19th century, the mature woman was the ideal, and those little girls and young women aspired to be more mature,” Jurow says. “There was definitely a whole movement after World War I when there was a rejection of maturity because these old people got us into horrible war. Now, we just want to forget about that and go back to childhood and be youthful. And it was one of the first times when street style and what the young kids, even if they weren’t rich, were wearing and looking like that got noticed by designers.”

For the early screen tests of “Gatsby,” Martin pilfered recent lines of Prada and Miu Miu, both designed by Miuccia Prada. Since Ms. Prada happens to be a friend of Luhrmann’s, it wasn’t hard for Martin to recruit her to create 40 new looks for the film.

“At the beginning, we went through the Prada archives over the last 10 years or so or even longer,” Martin says. “I was surprised at how many of the clothes totally fit into a ’20s vernacular, because I’d been doing a lot of 1920s research at the Metropolitan Museum of Art and at the Fashion Institute of Technology. And I was feeling direct parallels between the clothes. I prepared a document where I compared the clothes from Miuccia’s past collections with references that showed each particular dress’s antecedents.

“Miuccia said to me, ‘I don’t think I ever think about the ’20s. I only think about periods that I’ve lived or have had an association with through my family—the ’40s, ’50s, ’60s, ’70s,’” Martin continues. “But she was interested in the collaboration because she liked the idea that there were these subconscious themes that have been coming out of her work.”

Despite the drop-waists, flapper bobs, and cloche hats, the modern nature of the women’s Prada couture is startling when you compare it to the men’s clothing, which excepting some too-tight pants, is pretty accurate. Brooks Brothers, a company that was selling suits in the 1920s, supplied the three-piece suits, Windsor ties, and bowties, as well as casual cardigan sweaters and saddle shoes. The men in the film also sport proper headwear—straw boaters, fedoras, and golf caps—as well as round-framed sunglasses. Tom Buchanan (played by Joel Edgerton) even appears in period-perfect riding clothes with riding boots and jodhpurs.

“In general, everybody’s clothes were maybe a little more fitted than they would’ve been, but gentlemen were wearing very snuggly fitted suits at the time,” Jurow says. “I know some Art Deco Society gentlemen I’ve talked to had quibbles about tie widths and lapel widths and the like. But at least the filmmaker didn’t have their character’s pants sagging or anything completely wrong like that.”

If anything, Baz Luhrmann’s “The Great Gatsby” has sparked more interest in the Roaring Twenties. Jurow says attendance swelled at this summer’s Gatsby Summer Afternoon and she’s been fielding calls all summer from fundraising groups asking for tips on how to throw a “Great Gatsby” themed party.

“She was the wrong costumer to get the job if she can’t see the beauty in the real 1920s silhouette.”

“As far as keeping to the spirit of 1920s, they did a great job,” Jurow says. “If you watch that trailer from the 1926 silent, it has a bunch of girls diving into a pool and then running up the stairs in their bathing suits. That’s a lot like the way the parties were shown in Baz Luhrmann’s movie.”

“The best review I read of the film summed it up by saying the film was about ‘rappers and flappers,’” Walford says. “Luhrmann tried to make the story relevant by interpreting the 1920s in a way that would appeal to today’s audience. To that end, I think Luhrmann, and everyone associated with the film, did a splendid job.”

While the latest film might not have much to teach us about what life was actually like in 1922, it definitely tells us something about the collective fantasy we have in 2013 about the Roaring Twenties. And perhaps more importantly, it reveals what we as a culture consider sexy and decadent today.

Fashion Designs and Illustrations from the 1920s