Hitch apparently borrowed numerous visual ideas and plot points from Niagara. In fact, Vertigo can even be seen as his response to that film.*
The two movies share many similarities. Both stories concern a mentally unbalanced man who takes an obsessive – and possessive – interest in the beautiful leading lady, which leads to betrayal and tragedy.
In Hollywood, sexy blondes have always guaranteed tickets sales better than any other gimmick yet devised. Back in the day such idols as Jean Harlow (the original Blonde Bombshell) and Jayne Mansfield oozed sex from every curve. Monroe played that game better than anyone and in Niagara, her breakout role, something new sizzled on to the screen. In 1953, the New York Times famously gushed:
“Obviously ignoring the idea that there are Seven Wonders of the World, Twentieth Century-Fox has discovered two more and enhanced them with Technicolor in "Niagara," which descended on the Roxy yesterday. For the producers are making full use of both the grandeur of the Falls and its adjacent areas as well as the grandeur that is Marilyn Monroe.”
“I’ve never been very keen on women who hang their sex round their neck like baubles. I think it should be discovered. It’s more interesting to discover the sex in a woman than it is to have it thrown at you, like a Marilyn Monroe or those types. To me they are rather vulgar and obvious.” (Italics mine.)
“We have all seen women who exaggerate their physical attributes to a point where they can hardly be ignored. Men may stop and stare at such women. They may even show a lively interest in meeting them. But a man who does manage this kind of meeting may be disappointed to learn that his new friend has very little mystery about her, once he knows her name.
“As for myself, I prefer a woman who does not display all of her sex at once – one whose attractions are not falling out in front of her. I like women who are also ladies, who hold enough of themselves in reserve to keep a man intrigued.... When a man approaches her, the audience should be led to wonder whether she intends to shrink from him or tear off his clothes.”
Hitch's leading ladies were the antithesis of the typical Hollywood vixen. While the latter paraded their voluptuousness in a wardrobe that barely skirted the Production Code of the time, Hitch’s blondes kept their lithe bodies concealed under demure suits and other high fashion straightjackets. Other Hollywood stars approached their leading men with a come-on, but Hitch’s leading ladies could be off-putting. By working against the grain of Hollywood stereotypes, this British gourmand created something distinctive, if not unique: the iconic Hitchcock blonde. Other directors and actresses have been playing catch-up ever since.
*Taken as a whole, Niagara plays a minor role in the storytelling of Vertigo. There are several very important antecedents to Hitchcock's film: Portrait of Jennie, the Pygmalion stories from ancient Greece through George Bernard Shaw’s play of the same name and the 1956 Broadway hit My Fair Lady (which theater-loving Hitch very likely saw) are the most noteworthy. In its title sequence, Vertigo’s direct origins are credited to Boileau-Narcejac’s French novel D’entre les morts.