So why did they so quickly evolve into psychologically bleak depictions of damaged souls?
Among the rocks and dust of an Arizona canyon a man and a woman want to kill each other.
Each draws closer – gun in hand and they take turns to fire – inflicting wounds.
Yet between each shot the desire they feel for one another overwhelms them.
Here love reveals itself as murderous and murder proves loving.
Mortally wounded the woman crawls through the dust so they may die – stilled at last – in each other’s arms.
The scene is over-the-top – it is preposterous and yet in being so it is also exceedingly magnificent.
From Duel in the Sun (1946) – David O Selznick and King Vidor’s delirium-dream of a movie – this moment encapsulates the operatic astonishment of the postwar Hollywood western with a shootout that sets the tone for the genre’s descent into hallucinatory strangeness.
From then on the vast distances of the American landscape would be matched by the depth of fall into the human psyche.
Until then the western had stood as a realm of almost heraldic simplicities – a moral landscape in which the good and the bad square up; black hats versus white hats and all stays firmly in its place – especially the foundational dominion that is America itself.
Within a pristine wilderness new disconcerting complexities became manifest.
Neurosis and social disorder itself could ascend to the status of legend – the petty problems of the individual soul raised up into something archetypal.
Yet at times even the fixed landscape becomes estranging.
Film noir finds itself in black and white and shadow – the postwar western realises itself in colour and glare.
The director Anthony Mann’s grand postwar westerns belong to pure air and light’s gift of softness.
But his films are the exceptions to the Trucolor Technicolor or Eastmancolor rule.
Edward Dmytryk’s Warlock (1959), which features along with Duel in the Sun and a dozen other strange and impressive films in a BFI season of psychological westerns this month – better exemplifies the western look.
The palette is harsh and lurid – the earth is red – the men sunburnt and stubbled – the characters move in sweat grime and dust.
It is a fitting world for a genre that would seek to discover the soiled self in the previously unsullied icon.
Some of these postwar films were peculiar enough to bewilder their first audiences.
Even by the standards of the time it is a movie that operates at an uncomfortable pitch of excess and emotional extremity.