In John Ford's Western My Darling Clementine (1946), the lighting adds to the gritty and harsh nature of the landscape, the town, and the characters. Cinematographer Joseph MacDonald relies heavily on source lighting for dramatic effect. Much of the film is shot with low-key lighting without the use of much fill light for the same purpose. There are also strong signs of the direction of the light, suggesting where the source lies. Day-for-night photography is used for many of the exterior night scenes, giving added dramatic effect and making the night sky appear at times to be on fire.
The film is structured on contrasts, and the low-key lighting similarly creates visual contrasts:
The film's theme is the coming of civilization to the West. The western town of Tombstone becomes in Ford's poetic film the point where savage forces (the wild countryside, the rugged Monument Valley backdrops, the brutish Clantons, the Mexican whore Chihuahua) and civilized forces (the urban barber shop, dining room, the new church and school, the 'respectable' Earps, Doc Holliday's cultivated learning, Clementine the schoolmarm) meet (Dirks).
The opening sequences show the use of filters to bring out the sky and the clouds over Monument Valley as the Earps bring their cattle across the valley floor. The lighting through most of this opening sequence evokes the documentary which uses only natural sunlight as a source, adding to the realism of the scene and contributing to the grittiness and harsh look of the landscape. This is not a Western that prettifies the West and its denizens. Instead, Ford approaches the West here as a hard place to live and as a place peopled by hard people. Those who seem to "belong" to this landscape will be contrasted with Clementine, who clearly does not belong, especially in the eyes of Wyatt Earp.
The lengthy sequence in the town of Tombstone that first night shows the power of source lighting as t...