Ansel Adams: "The Zone System"

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The Zone System is a photographic technique developed by Ansel Adams and Fred Archer in the 1930s. It provides a systematic approach to exposure and development in black-and-white photography.

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The Zone System is a method of understanding and controlling the exposure and development of the negative, and how to vary that exposure to get the desired results.

 

Printing, exposure and development are all interconnected. The results from one can be affected by the other. This gives reason to the fact that the more precise your exposure, the less you will have to compensate during the development and printing stage.

 

The Zone System was developed by Ansel Adams and Fred Archer as a simple procedure by which a photographer could control exposure. Before this procedure came into effect. The photographic industry had already developed and standardised f-stops and shutter speeds as a method of controlling light. But this posed a dilemma for the more experienced photographer. And a lot of them began to ask the question; "How much light must fall on the negative to get the photograph I want".

 

The zone system recognizes the limitations of film and the digital image processor and it works within these limitations to accommodate for the vast amount of colours, tones and brightness variations found in nature and around us. By applying the zone system and utilising its scope in photographic practice, we can produce images that exemplify its precise accuracy. We are then able to reproduce images of nature with a wider tonal range and varying degrees of brightness with only a slight unnoticeable difference from that of the original.

 

Archer and Ansel used the spectrum of print values, from black to white, using f-stops as the standard of measurement. They assigned a zone to each value that each f-stop of exposure produced. This produced what is known as the "Zone Scale". A visual representation of print values from black to white.

 

The camera is calibrated to take a reading of 18% grey as spot-on correct and accurate. The camera will assume that this is the desired amount of light reflectance. It will then average the light reading of the extreme shadows or highlights to produce an over-exposed or under-exposed image. The Zone System eliminates this problem by assigning these specific values to each zone.

 

A light meter averages the value of all light it receives. Based on this average of light it then assigns a suggested setting (Shutter speed/f-stop), which results in the same exposure. This will be an exposure for a mid-grey, which Ansel and Archer classified into Zone V.

 

 

The standard eleven is the most commonly used by photographers. The meter reading is in the middle of the scale. The zones are numbered 0 through X. Zone 0 represents the maximum black that the printer can produce. Zone X represents pure white - no image. The nine zones between are each equivalent to one increasing f-stop of exposure. Decreasing or increasing in value from Zone V. The Zone system is the point value that will be produced when the film is properly exposed and developed for that zone. The photographer will then determine the exposure, and the exposure will then determine the zone he will get. The photographer's main starting zone will be the zone value V. The Zone System scale is a series of tonal values each value being the equivalent of one full f-stop.

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The eleven Zones:

 

0:- Black, no texture or detail, pure black.

I:- Near black, shadows in faint light or rooms without light, the beginning of gradation.

II:- Dark coal-black only subtle textures are visible.

III:- Very dark grey - distinct shadow texture is visible, dark shadow.

IV:- Medium dark grey - slightly darker skin, dark foliage or shadows in landscapes.

V:- Medium grey 18% grey - darker "white" skin or lighter "black skin," light foliage or the dark blue of a clear blue sky. (Your meters suggested reading)

VI:- Mid-tone grey, average "white" skin or shaded areas in the snow on a bright sunlit day, sharp fine detail visible.

VII:- Bright light grey, the highest zone still holding detail, weathered paintwork, silver hair, and a concrete walkway in sunlight.

VIII:- Light grey-white, shows last texture at least a minimum, but no detail, reflected highlights from the light-coloured skin, gradation still exists.

IX:- Key white or pure white, snow in the bright sunlight, no detail or significant texture visible, lightest gradation values.

X:- Paper base white, no image recorded in print.

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How to use and put the Zone System into practice.

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For example, if I wanted to photograph a perfectly smooth, round, white stone, and I have my spot meter with me, I would meter the stone and set my camera controls to the same specifications given by the spot meter. Am I doing this correctly? According to Ansel Adams' Zone System, my meter will give me a reading for a dull, 18% medium grey. This isn't correct, as I know by looking at the pure white stone. If I take this reading at face value and input it into my camera, the printed exposure for that image will portray the white stone as a dull medium grey. I don't like this result, as it's not an accurate indication of the stone's physical features.

If I follow the procedure as laid out by Ansel Adams, my pure white stone should be at Zone VIII (light grey-white showing some texture at a minimum), but my meter is indicating Zone V. I will then need to give the pure white stone more exposure than indicated by the meter. I opened the lens three f-stops from what was suggested by the meter. This will place my setting at Zone VIII. The pure white stone remains a constant; that is a given. All I have done is change the exposure. I am trying to establish the tonal value by using Ansel Adams' Zone System procedure. I have mentally visualized the changes in the tone value for the print as I change the exposure, either going up or down from my starting point at Zone V.

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Another example would be if you were in the Lake District during the winter season. You want to photograph the snow-covered peaks. Similar to the above method, you will also take a meter reading for the snow, which gives a suggested shutter speed of 1/500 and a corresponding aperture of f/16. According to the Zone System, if you use these settings, the image will be a dull 18% grey, "Zone V". The Zone System indicates that snow in bright light falls within Zone IX. This is four stops above Zone V (the 18% grey). It would then be logical to open up four stops to f/4 and shoot at 1/500. This will give the image a more natural white snow appearance.

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However, the Zone System is not limited to a single object. Our world consists of different scenes. For ease of understanding the procedure, take the above example of the snow-covered peaks in the Lake District. These peaks will be surrounded by a bright blue sky and white clouds in the background. The peak area will have various rock formations of different colour densities. As a photographer, I want to capture as much detail as possible, especially the different rock formation densities and the shadows. I meter for the shadowed areas of the rocks, which gives me a reading of 1/60 with a corresponding aperture of f/2.8. I want to capture that bright blue sky, so I take a second reading, which gives the same shutter speed but a different aperture of f/16. I have mentally visualized that this scene has high and low levels of contrast, so I will need to expose the shadows to capture the detail in these different tones. Using the Zone System, I can verify that the shadowed areas of my scene fall into Zone II. To capture this scene, I will then need to open up three stops and shoot at 1/60 at an aperture of f/8. But this will result in losing a lot of the highlight details of the bright blue sky. This isn't really what I want; it doesn't achieve the desired result I initially wanted.

 

This brings me to the second part of Ansel Adams' Zone System. The Zone System incorporates exposure and development techniques. By varying the development time to a certain degree, plus or minus according to the given f-stop scale, using Ansel Adams' procedure, we will then be able to control Zone placement by controlling the development of the negative. As developing time is increased, negative densities also increase. This will also increase our highlight densities within our image. So it gives reason to state that contrast increases with increased development time. This will be obvious. From this, we can determine that highlight density is controlled by developing time and shadow density is controlled by exposure. So it would be logical to assume that any additional developing time would cause "over-developing," causing the highlights to move up the Zone System scale by two zones. Lowering the highlight densities will bring it down to two zones.

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Ansel Adams used a large format "sheet" film, which gave him more control over the development of each negative, allowing him to isolate each section of the negative and vary its development. This is all very good, but what if you are a digital photographer? The Zone System will still apply, and you can utilize both the dodge and burn techniques. Dodging is when a photographer uses a specific software package like Adobe Photoshop to lighten certain areas of the image. Burning refers to the darkening of specific areas.

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Practical Application of the Zone System

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Example 1: Photographing a White Stone

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If I want to photograph a perfectly smooth, round, white stone with my spot meter, I would set my camera controls to the specifications given by the meter. However, the meter will give a reading for an 18% medium grey, making the white stone appear as dull medium grey in the image. To correct this, according to Adams' Zone System, the white stone should be at Zone VIII. By opening the lens three f-stops from the meter's suggestion, I can achieve this.

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Example 2: Photographing Snow-Covered Peaks

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In the Lake District during winter, photographing snow-covered peaks requires a meter reading for the snow. The meter suggests a 1/500 shutter speed and f/16 aperture, producing a dull 18% grey image (Zone V). According to the Zone System, bright snow should be in Zone IX, four stops above Zone V. Opening up four stops to f/4 at 1/500 will give a more natural white snow appearance.

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Managing Different Scenes

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The Zone System applies to complex scenes with varying elements. For example, photographing snow-covered peaks with a bright blue sky and different rock formations requires multiple meter readings. By metering shadows (1/60 at f/2.8) and bright sky (1/60 at f/16), and visualizing high contrast levels, the photographer might need to open up three stops to f/8 for shadow detail, although this may sacrifice highlight details.

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The Role of Development Techniques

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Adams' Zone System includes exposure and development techniques. Varying development time controls Zone placement. Increased development time raises negative densities and highlights densities, increasing contrast. Highlight density is controlled by developing time, while shadow density is controlled by exposure. Over-developing moves highlight the Zone System scale by two zones while reducing developing time brings them down by two zones.

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Applying the Zone System to Digital Photography

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Adams used large format "sheet" film for greater control over negative development. Digital photographers can still apply the Zone System using dodge and burn techniques in software like Adobe Photoshop. Dodging lightens specific areas while burning darkens them.

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​​​A digital zone system:-

 

Zone 0 = -5EV (pure black no detail) - black nighttime skies.

Zone 1 = -4EV (black, only a few details present) - very dark shadows.

Zone 2 = -3EV (black with some detail visible) - dark shadows, black clothing.

Zone 3 = -2EV (dark but full detail present) - blue sky, dark green leaves, dark skin.

Zone 4 = -1EV (dark tones with full details visible) - dark skin, general appearance.

Zone 5 = 0EV (middle tone 18% full details visible) - light skin, stonewashed jeans.

Zone 6 = +1EV (light tone but with full details visible) - light skin.

Zone 7 = +2EV (white with some details present) - paper, white walls.

Zone 8 = +3EV (white with a hint of detail present) - overexposed, pure white backgrounds.

Zone 9 = +4EV (pure white no details present) - reflections, lights.

 

 

If your spot meter gives you a reading of a middle 18% tone grey "0EV". If you aimed it at a grey card, and the meter didn't read for a "0EV", you will need to adjust the exposure until the meter read "0EV". By doing a few tests using a piece of white paper instead of a grey card. You will be able to find that the white paper is 2 stops brighter than the grey card (+2EV). And you will need to adjust for this as your meter will give off a reading of +1.3EV. So logic will dictate that you amend this by adjusting it until it reads +2EV. This results in a longer exposure which in turn will produce a brighter image. This can only mean one thing. Ansel Adams's Zone System can be applied digitally to assign exposures to scenes with a known brightness.

 

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