The element is seen in some of the earlier black-and-white films as well, though the cool blonde image is most clearly developed in Hitchcock's color films in the 1950s. The way the cool blonde was used in traditional film noir shows how different Hitchcock is in his use of the figure. Barbara Stanwyck in Billy Wilder's Double Indemnity is the more powerful woman who pulls the man's strings, while Hitchcock's women are more likely to be damaged (as is Marnie) or over-reaching (as Grace Kelly is in Rear Window). Hitchcock's films have features of the film noir while treating these features in a unique manner, but it is likely that the film noir influenced the development of some of these elements, notably stylistic ones related to cinematography and art direction, but also character and plot in some degree.
Wood, Robin. Hitchcock's Films. New York: A.S. Barnes, 1965.
Cawelti, John G. "Chinatown and Generic Transformation in recent American Films." In Film Theory and Criticism, Gerald Mast and Marshall Cohen (eds.), 503-516. New York: Oxford University Press, 1985.
for the proper environment for the darkness of the human soul was the black-and-white image of the city in the 1940s and 1950s:
In both these films, Hitchcock utilizes some of the stylistic elements of the film noir, with a concentration on dark city streets, low-key lighting, a threat from nowhere, crime, and mental instability. In a number of films, Hitchcock also uses a variation on the femme fatale that is so common in the film noir, the woman who acts as a lure and who proves to be more dangerous than the male. in Hitchcock, though, these women are more likely to be playing at being tough rather than actually being touch. The women in Hitchcock's Golden Period are blonde, cool, reserved, capable, and yet often foolhardy in the way they assume their own power. They tend first to be images rather than real women--Kim Novak in Vertigo shows the importance of image to the males in these