How did Gregg Toland help create the visual style of Citizen Kane?

Cinematographer Gregg Toland played a pivotal role in establishing the groundbreaking visual style of Citizen Kane through his mastery of chiaroscuro and deep-focus photography.2

To achieve a photographic depth of field that mimicked the perceptual range of the human eye, Toland utilized several technical innovations:1

• Advanced Equipment: He employed newly available Eastman film stock with increased light sensitivity, combined with plastic-coated wide-angle lenses opened to smaller-than-normal apertures.1
• High-Intensity Lighting: The use of high-intensity arc lamps allowed for the necessary exposure levels to maintain focus across multiple planes of depth.1

These techniques enabled Orson Welles to stage characters in several different planes of depth within a single scene, creating the film's signature deep-focus sequence shots. Toland’s innovative lighting and focusing methods are widely recognized as essential contributions to the film's enduring influence on cinema.123