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The Zone System Explained

By Association Co-Founder Christopher John Ball

The Zone System is a method of exposing, developing, and printing monochrome images and is based upon pre-visualising the subject matter. By pre-visualising I mean thinking about what you want the final print to look like, before you make the exposure, and then adjusting exposure and/or development, etc. in order to create that print as pre-visualised. I am aware that there are those who have tried to use the Zone System with colour materials, I feel that the nature of colour materials do not allow for satisfactory results.

When discussing the Zone System one has to mention Ansel Adams who is believed to have developed the system in 1941. He used the Zone System extensively within his photography. Many photographers have used the same methods as Adam's, whilst others have adapted his techniques to suit their own working practice.

The Zone System
Zone I The darkest black possible for the chosen paper/film emulsion.
Zone II Not as dark as Zone I but still no visible detail.
Zone III Darkest shadows with details are starting to appear, e.g. black hair.
Zone IV Medium dark values like brown hair and blue jeans.
Zone V Middle grey values. Most light meters are set to give a reading based on zone V
Zone VI Darkest highlight values, such as Caucasian skin and light hair.
Zone VII Bright values with texture and detail, such as sand and white/ivory clothes.
Zone VIII Whitest white but still showing details.
Zone IX No details but not as white as Zone X.
Zone X The whitest white possible for the paper/emulsion. Also known as base white.
The N-Development method is a system of exposure/development and is used to place the important shadow details in Zone III (see below) and the important highlight details in Zone VII, thus giving a normal contrast range of 5 stops. The first step is to set the exposure in such a way as to place the important shadows in Zone III. This is two stops under mid-grey/Zone V. The film is the processed according the appropriate N-Development plan as follows. Note that development times are a general guideline and should be adjusted according to your individual chemicals, equipment, etc.
N-Development Table
Subject Brightness Range: N-Development: Development Time:
3 stops N Plus 2 100% increase
4 stops N Plus 1 50% increase
5 stops N normal time As specified
6 stops N Minus 1 20% decrease
7 stops N Minus 2 40% decrease


N-Development obviously works best with sheet film as each sheet can be processed separately. If you are using roll or 35mm film you can use the above method but it is possible to expose as instructed above but develop the film normally. Contrast control can then be adjusted when the print is made.

Many photographers test each camera lens they use, due to resultant light loss due to transmission factors. One would have to test each lens used, including any enlarger lenses.

Film is often bought in bulk. The photographer shooting tests to ascertain the 'actual' film speed rating. Though a film may have a nominal speed rating of 400 tests may show that the actual rating varies. I have known films, that after testing, are really 200. This obviously has an effect on your subject placement.

To test your film a 'Kodak' 18% Grey Card is required. Photograph this card, making sure the card fills the frame, in balanced/even lighting. Make an exposure based upon the meter reading and then make additional exposures using each available aperture. DO NOT adjust the shutter speed. For example, if the meter suggests an exposure of 125th of a second at f8 make an exposure then make additional exposures at f5.6, f4, f2.8, f11, f16 all at 125th of a second. Develop the film as per instructions.

Contact print, using a 'step wedge' to judge the contact print exposure, and then check the resultant images, comparing them with the grey card. Given that most photographic meters are built to give a reading based upon the 18% grey card, the frame that is nearest in tone to the card and the exposure used is noted. If the meter reading suggested 125th second at f8 but the negative nearest in tone to the card was obtained at f5.6 it can be seen that there is a one stop difference.

This would suggest that the film should really be rated at 200 when using that specific equipment combination. Test this by undertaking another experiment photographing the grey card, this time altering the meter to suggest that a film of 200 is being used. Again compare contact print and card. If they match, rate the film at 200. If not adjust and test again. A 400 film coming in at 200 is an extreme example. It will often be found that the first test shows that the nearest equivalent to the grey card is in fact between two negatives and that further tests are needed. Remember the final result is only valid with that batch of film used within a specific camera,lens, enlarger combination.

A word of advice. Don't get hung up on the zone system. Creativity is of far greater importance; the zone system is there to be used as a tool and should not become a hindrance to creativity.

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