De-mystifying Ansel Adams "zone system".


the fool on the hill
Dec 11, 2005
Aurora, IL
This is an excellent read!
Ansel Adams was a genius. He was methodical in his work and extremely demanding in terms of the quality of his prints. Those who admire his work or attempt to imitate his methods are often perplexed or intimidated by the results. It seems that a vast majority of people believe that Ansel Adams? techniques, often shrouded in mystery, are impossible to master. This is simply not so. This article is dedicated to demystifying the clever, yet relatively simple Zone System so masterfully devised by Ansel Adams and perfected by other virtuosos of photography.

To fully understand and appreciate the Zone System, one must first have at least a basic understanding of photography nomenclature. Mastery of the Zone System requires significantly more dedication to the fundamentals of photography and lots of practice. I will assume, for the purposes of this article, that my readers have a basic command of the principles of exposure - the interplay of light, shutter speed and aperture.

The f-stops here! The Zone System focuses on two very important aspects of photography ? image exposure and development, which naturally centers on the f-stop (the size or opening of the aperture as expressed by a number indicating the amount of light transmitted through the lens). Unlike the vast colors, tones and brightness found in nature, the Zone System recognizes the limitations of film and/or digital image processors and works within these limitations. Sadly, no single camera, lens or film available today can absolutely equal nature?s immensity. However, by utilizing the techniques of the Zone System we can reproduce, as precisely as possible, images of nature that exemplify its tonal ranges and varying degrees of brightness with little discernable difference.

Imagine a ladder. The bottom rung of the ladder represents pure black (Zone 0). The top rung of the ladder represents pure white (Zone 9). The mid-point of the ladder (Zone 5) represents 18% gray or the accepted average reflectance of light from a given subject, which is interpreted by your camera?s integrated light meter as the correct exposure for both B&W and color images. From the mid-point, Zone 5, each sequential step or zone represents a change of one f-stop. Zone 4 requires an exposure of one f-stop less than your meter reading (or Zone 5). Conversely, Zone 6 requires an exposure of one f-stop more than your meter reading. Therefore, the entire Zone System encompasses a nine-stop differential, which is more than adequate to address even the most daunting high contrast scene in nature.

Now, let?s add values to these Zones. These are values Ansel Adams himself associated with the nine Zones.

Zone 9 ? known as key white or pure white ? pure white paper or snow in bright sunlight.

Zone 8 ? gray/white, near white ? distinct highlight detail, like a white wall in sunlight or brilliant surfaces in flat light.

Zone 7 ? light gray ? pale ?white? skin, a concrete walkway in sunlight.

Zone 6 ? mid-tone gray ? average ?white? skin or shaded areas in snow on a bright, sunlit day.

Zone 5 ? medium gray or 18% gray ? darker ?white? skin or lighter ?black skin,? light foliage or the dark blue of a clear blue sky.

Zone 4 ? medium dark gray ? slightly darker ?black? skin, dark foliage or shadows in landscapes.

Zone 3 ? very dark gray ? distinct shadow texture is visible.

Zone 2 ? dark gray/black ? only subtle textures are visible.

Zone 1 ? near black ? shadows in faint light or rooms without light.

Zone 0 ? key black or pure black ? carbon or photo paper black.

Remember your camera is calibrated to read 18% gray as ?correct? and assumes that is the desired amount of light reflectance. Thus, it will average the light readings of extreme shadows or highlights resulting in over-exposed or under-exposed images, respectively. The Zone System eliminates this problem by assigning these familiar ?values? to each zone. The key to success with the Zone System is to carefully pre-visualize your subject and apply the correct Zone values to the important exposure areas. Then, you must adjust your exposure settings accordingly to accurately produce the results you want.

Let?s say you are on vacation and want to take a photo of snow-covered Pikes Peak. It?s a typical sunny day in Colorado. You take a meter reading of the snow, which suggests a shutter speed of 1/500 and a corresponding aperture of f/16. If you snap the photo using these settings, the resulting image will be dull 18% gray. According to the Zone System, snow in bright sunlight falls under Zone 9, which is four stops above Zone 5, or 18% gray. Therefore, you must first open up four stops to f/4 and shoot at 1/500. Now, your photo will clearly show the brilliance of the white snow under the Colorado sun.

What should you do if you want to photograph an interesting rock formation with a bright blue sky and fluffy white clouds in the background? The rock formation is moderately shadowed with lots of texture. You want to bring out as much detail in the rock formation as possible. You take a meter reading of the shadowed areas of the rock, which indicates a shutter speed of 1/60 with an aperture of f/2.8. Then, you take a reading of the sky, which indicates the same shutter speed but an aperture of f/16. Keep in mind that in high contrast scenes, you MUST expose for the shadows if you want to reveal the shadow details. Sometimes this means sacrificing some of the highlights in your subject landscape. You decide that the shadowed areas fall within Zone 2. Therefore, you must stop down three stops and shoot at 1/60 at f/8. Of course, this means that you will lose some of the highlight detail from the bright sky. Don?t despair. All is not lost.

Recall that the Zone System integrates nine f-stops. Yet, the latitude or exposure range of most readily available film varies from a low of three f-stops to a high of seven f-stops. Likewise, photo paper, in general, has a range of no more than five f-stops. How, then, can you compensate for the limited latitude of film and photo paper? The Zone System incorporates both exposure AND development techniques. Ansel Adams used large format ?sheet? film affording him more control over the development of each individual negative. By varying development time, plus or minus according to a comparative f-stop scale, Ansel Adams was able to effectively defy the limited latitude of his film and photo paper.

Contrary to the photographic rule of exposing for the shadows, you should develop film for the highlights. Concentrating on the range of brightness in a given image negative, Ansel Adams established the following development scale:

Normal development time, plus 100% @ 3 stops

Normal development time, plus 50% @ 4 stops

Normal development time only @ 5 stops

Reduce normal development time by 20% @ 6 stops

Reduce normal development time by 40% @ 7 stops

The Zone System works best with large format ?sheet? film since you can isolate each section of the negative and vary its development time. While you can apply these techniques to roll film, it would require identical exposure for each frame, which isn?t very likely or practical. If you are a digital photographer, like me, or a roll-film photographer hoping to take advantage of all the aspects of the Zone System, you can utilize both the burning in and dodging techniques. Burning in refers to darkening specific areas of your image. Dodging refers to lightening specific areas of your image. For digital applications, you can use the tools in Adobe Photoshop. For film, you can appropriately mark your prints for these advanced development processes.

By employing both the exposure and development techniques of the Zone System, you will be able to produce amazing images like those of the masters. Ansel Adams was, indeed, an innovator. He created a unique and valuable tool, in fact, a legacy for all photographers. Fine Art Photography wouldn?t be the same without the Zone System.

I hope this article will help you to realize that the Zone System is not complicated or mysterious at all. It merely requires a reasonable investment in time, effort and careful but straightforward calculations to achieve extraordinary results. If you wonder whether or not the effort is worth it, simply look at a handful of Ansel Adam?s photographs.

More on the zone system.