Tuesday, January 27, 2009

The Zone System

Because we are doing black and white this month, I thought I would share some photo history. This post is not meant to be a tutorial about the zone system. In fact, I never use it in my own work, most likely because I tend to be more intuitive (a euphemism for undisciplined?) rather than methodical. However, given that many of the great masters swear by the zone system, you may want to know about it.

A brief history of the zone system

Ansel Adams and Fred Archer created the zone system around 1941. I think it is safe to assume that you have heard of Ansel Adams and seen some of his stunning black and white landscapes. Every poster store in America carries reproductions of his work. Fred Archer, on the other hand, has never achieved a comparable level of popularity, and is often eclipsed by Adams even in accounts of the zone system. Some would argue that Archer first came up with the idea and that Adams, after having read about it in a series of articles, helped to formalize the system.

The goal of the zone system is to have better control over exposure. The first step in achieving good exposure is to visualize the entire photograph and to study the gradations from blackest black (zone 0) to whitest white (zone 10). You can see a good chart of the 11 zones (typically labeled with roman numerals) on Wikipedia. Ansel Adams only considered zones I to IX to be useful for film density.

I asked my assistant, Lucy, who uses the zone system all the time, to help out by labeling one of her photos according to zones:

Photo by Lucy Call

If you are just reading to get a basic understanding of the zone system, you might be satisfied by looking at the photo above and then skipping to the conclusion, but if you want to plunge into the more technical aspects and try it out (this is a darkroom process), here is an explanation from Lucy:
    1. You must find your effective film speed. With large format camera and B&W sheet film, I use Kodak T-Max 400, expose five sheets of film. You bracket these exposures, so that one exposure is right on and one is ½ stop under and another is 1 stop underexposed. Then the other two are ½ stop over exposed and 1 full stop overexposed. These are all developed at the suggested time for your film and developer type. Then to determine the effective ISO, you look at the different exposures and find where you think your values, mainly shadows, look best. So if you like the one that was exposed for what the meter said, then you would shoot your film at 400. I believe that the ½ stop underexposed would be ISO 320 if I remember correctly.
    1. Now that you have your ISO, you want to find your effective developing time. So expose 5 sheets of film at your new ISO and develop each sheet. If your suggested developing time was 7 ½ minutes, then you would put one sheet of film into the tray of developer and wait thirty seconds and then another and wait thirty seconds and another and so on, until the first sheet has been in the developer for 8 ½ seconds and the last one put in has been in it for 6 ½ seconds. Once this is finished you can determine your effective developing time. Look at highlights.
    2. Then go shoot and use the zone system. The first thing I do is look to see what I think should be in zone III (my darkest darks that still have full detail) and then I meter that and stop down two because it is giving me middle gray. Then with that I meter where other values will fall accordingly. If I don’t like where some of my highlights are falling than I adjust that with my developing time. So if my highlights needed to be brighter, I would push my developing or develop for longer. You determine this by step 2.
If you read Lucy's explanation, you can see why someone as distracted as myself might shy away from that process. If, on the other hand, you want to learn more, check out usefilm's article, the Wikipedia entry, the Luminous Landscape article, and a host of books for further reading.

But even if you find the system not applicable to your needs or too intimidating, your awareness of the zones will help you better appreciate black and white, Archer and Adams, and the photographic process.


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