Several reasons have been put forward for the film being in black and white.
John Ford once claimed it added to the tension, however others involved with production said Paramount was cutting costs and so they had to make the movie on sound stages at the studio. Without the budget restraints, Ford would have been in Monument Valley using Technicolor stock. It has also been suggested that since both
John Wayne and
James Stewart were playing characters thirty years younger than they actually were (Wayne was 54 when the movie was filmed in the autumn of 1961 and Stewart was 53), the movie needed to be in black and white because they would never have got away with it in color. The age difference was particularly noticeable in Stewart's case, since he was playing a young lawyer who had only just graduated from law school and had moved West without even practicing law back East.
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