Marylin Monroe: The star with marbles in her bra

Norma Jeane Mortenson, then Baker, Dougherty, DiMaggio and Miller died 50 years ago this August of a barbiturate overdose, aged 36. In a little over 15 years, the woman we know as Marilyn Monroe had established herself as an actress, singer, producer and, above all, a sex symbol, despite her protestation that "a sex symbol becomes a thing. I just hate to be a thing".

Yet reified she was, more so than any star of her age. Monroe endures as the great female icon of the 20th century, a sumptuous 5ft 51/2in, 36-22-36-inch welter of contradictions comprising voluptuousness and vulnerability, innocence and experience, part angel, part whore.

The latest attempt to analyse Monroe's image comes with a new exhibition at the Getty Images Gallery in London: 66 largely unseen Monroe images from its 90 million-strong archive, plus new video footage and 12 of her most memorable outfits. Even prior to its opening, viewers were storming the doors, drawn by the totemic name "Marilyn". "From the point of view of images sold, Monroe is only rivalled by Audrey Hepburn as the female idol in our top 10," confirms gallery director Louise Garczewska.

Originally, it was Monroe that Truman Capote wanted to play Holly Golightly in Breakfast at Tiffany's, which might have proved the role of her life. While the teenage Hepburn had endured the challenges of the Second World War as a volunteer nurse in a Dutch hospital, Monroe had survived a perilous childhood of material and emotional penury from which she was determined to emerge by recreating herself as an icon.

One of Monroe's better foster parents assured her that she would one day be a star like Jean Harlow and let the infant Norma Jeane wear make-up and have her hair curled. Later, the fledging starlet adopted her mother's maiden name of Monroe, as her heroine had assumed Harlow. "Marilyn" was chosen by a film executive for its sex appeal and "nice flow", despite the young starlet's initial dislike of it.

Where Norma Jeane had been a brunette, Marilyn was an ever more transcendent blonde. Her overbite was corrected during a stint at Columbia Pictures, a cartilage bump removed from her nose. Monroe's make-up artist, Allan "Whitey" Snyder, observed that it was during preparation for Niagara (1953) that they achieved "the look". It was all about juxtaposing light and shade to ensure that Monroe would look radiant by camera; specifically a black and white camera. She looks cartoonishly garish in one of two colour images included in the exhibition.

The actress had a characteristically sultry explanation for her ambition to remain pale but decidedly interesting. In September 1952, she declared: "I'm personally opposed to a deep tan because I like to feel blonde all over." The starlet slathered on layers of Vaseline, hormone cream, Erno Laszlo Active pHelityl Cream, or Nivea (meaning "snow white") to give a glow under studio lights, followed by a light film of foundation by Laszlo and powder by Anita of Denmark. This layering technique meant that, even in the more unstudied Getty images, light beams from her cheeks. This glow was augmented by the blonde down caused by the hormone cream. Monroe expert Gene London has maintained: "She had the heaviest peach fuzz beard of any actress in Hollywood. They [studio chiefs] wanted to remove the facial hair, but Marilyn absolutely refused. She said that when the light hit the fuzz it caused her face to have a soft glow, so they didn't have to photograph her through special lenses, lace, or Vaseline the way they did with so many stars."

Further tricks were used to shape her nose, sharpen her cheekbones, make her eyes look more deep-set, arch her brows, and emphasise her heart-shaped face. A plumper and fuller pout was created with five different varieties of lipstick and gloss: darker reds on the outer corners, lighter shades in the middle to lend dimension, with a highlighted cupid's bow and bottom lip. Her luminous face was framed by a halo of platinum hair.

It could take an hour and a half to achieve this chiaroscuro confection of highlights, hollows, lifts and contours. Its strength was that it somehow reflected her personality. As her third husband, Arthur Miller, wrote: "She was a whirling light to me then, all paradox and enticing mystery… lifted by a lyrical and poetic sensitivity that few retain past early adolescence." In the Getty images showing her promoting The Prince and the Showgirl (1957), her face shines forth with a lustre that renders Laurence Olivier a saturnine goblin.

Her body also shimmered, the lavish hourglass so excessive in the context of contemporary Hollywood scrawniness. The now fading gowns are unexpectedly tiny (largely UK size 8) until one consults the images in which they are worn, where some alchemy of femininity renders them all trembling, blancmange flesh. Marilyn was crammed into these creations. The still shocking, sheer, black beaded number she sported in Some Like It Hot was so tight that her then pregnant form had to be lifted onto Sugar Kane's piano.

Her physique may have varied slightly (especially during pregnancies, all of which ended in miscarriage), but its contours were established during the filming of Niagara; not least in the notorious scene in which she is shown from behind, wiggling the 116 feet to the Falls. The pink linen dress in which she made this journey appears blushingly innocent - not so when filled. As Constance Bennett remarked after viewing the film: "There's a broad with her future behind her."

Her heaving bosom was no less a focus. "She always wore a bra to bed because she didn't want her breasts to sag," says London. "Marilyn took to placing marbles in her bras, or she'd take three buttons… and sew the buttons together and place those inside her dress." Looking at the pert-nippled footage, one imagines this technique in action.

Monroe's clothes were often criticised. No less an authority than Joan Crawford carped at her "vulgarity". The gaudy physics of this "if you've got it, flaunt it" aesthetic were closely attended to. Hems were weighted to achieve the requisite cling, biases cut so tight that she could not sport underwear, a reputation that only added to her allure.

All this effort was as nothing without a means of recording it. More than any other actress, Marilyn manipulated the still photograph to publicise her attractions. She worked with some of the most influential artists of the day, including Henri Cartier-Bresson, Cecil Beaton, Milton Greene, Bert Stern and Eve Arnold. The latter enthused: "I never knew anyone who even came close to Marilyn in natural ability to use both photographer and still camera."

The Getty images tell a story of fresh-faced ambition, settling into the stylised features of her celebrity's height, before bloating into the confused final months recorded by The Misfits. Throughout, she is never anything less than compelling. As Matt Butson, vice-president of Getty's Hulton Archive, notes: "Monroe looks right through the lens at the photographer and at us - there's a relationship, contact. And when she's vulnerable - as she increasingly was - we see that vulnerability. Stars today are so tightly managed. We never see who these people actually are. Will they, like Marilyn, still be around in 50 years' time? I doubt that."