Zone system

In photography, the zone system is a technique invented by Ansel Adams and Fred Archer in 1939 or 1940. It is one of the earliest methods to give photographers systematic control of their images by precisely defining the relationships between their equipment and materials.

Overview for monochrome materials

The zone system separates the picture's tones into eleven zones, numbered using Roman numerals.

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: 0: Pure black

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: I: Near black

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: II: Dark gray / black

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: III: Very dark gray - the lowest zone with distinct shadow detail

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: IV: Medium dark gray

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: V: Medium gray (equal to Kodak's 18% Grey cards)

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: VI: Mid-tone gray

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: VII: Light gray

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:VIII: Gray / white - the highest zone with distinct highlight detail

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: IX: Near white

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: X: Paper base (pure white)

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The zone system is chiefly used when exposing film, and more specifically, when deciding how to render shadow areas. Generally, the photographer wants to expose the film for the desired tone and amount of detail in the dark areas of the composition, then alter the development time to affect highlight density.

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What makes the zone system so useful is the ease with which it translates desired effect to camera settings. Light meters will return the proper aperture (f-stop) and shutter speed to expose the metered area at 18% middle grey - equal to zone V. Each zone above or below zone V corresponds to one f-stop. So, for example, if a photographer desires the shadow values of the ground below a bush to be a very dark tone, but still holding detail (zone III), he or she would close the aperture two stops from the light meter's reading of the shadow area. The smaller aperture results in less light hitting the film and thus in darker shadow areas.

Related Topics:
Light meter - Aperture - F-stop - Shutter speed

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