Bruce Barnbaum - The Art of Photography - An Approach to Personal Expression

I learned about the seductive effect of the polarizer the hard way. I was photographing a color scene in the rolling, oak-covered grasslands of California near San Luis Obispo in the early 1970s. The leaves on the live oak trees were quite reflective and bright, the grasslands were covered with spring wild-flowers, and the blue sky had streaked white clouds. I used a polarizer to accentuate the contrasts and colors. At the nonpolarizing angle, the filter simply darkened the entire scene. But as I rotated it, the clouds began to pop out from the blue sky and the leaves on the oaks became progressively greener. I finally reached the maximum angle of polarization and was giddy with how colorful everything had become. It turned out that the resulting transparency was a complete dud! By eliminating the reflection off the leaves, I lost all the feeling of light and life—effectively turning the trees into blobs of deep color, as if they were painted. Somewhere between the nonpolarizing angle and the maximum polarizing angle I could have moderately accentuated the clouds against the sky, while at the same time retaining some of the brilliant light off the leaves and moderately enhancing their color saturation. It was a lesson learned.

Note

A polarizer can be misused by rotating it to its maximum polarizing angle. When this angle is used for color slides of dramatic landscapes and cloudscapes, the polarizer can make the sky oppressively blue-black.

It is easy—perhaps compelling—to gravitate toward the maximum polarizing angle because its effect can be intoxicating. Each increment in dramatic effect gains acceptability, making the next one acceptable and desirable as well. Always keep in mind the fact that believability can be pushed somewhat beyond reality—into a realm bordering on “super-reality”, heightened impact, and increased drama—but pushing too far creates a decidedly unreal and obviously contrived photograph.

Chapter 8. The Zone System of Exposure for Film

THE NEXT FOUR CHAPTERS deal with the practical aspects of making a photograph. Chapter 8 through Chapter 10 deal with traditional film exposure and printing. Chapter 8 explains exposure of the film negative or transparency for optimum effect. Chapter 9 explains development of the black-and-white negative for creative, personal interpretative purposes. Chapter 8 and Chapter 9 are so closely tied together that it is difficult to separate them effectively without leaving a temporary gap. The gap is tied together early in Chapter 9, so please read on until the explanation is complete.

(Note: development of color negatives and transparencies is not explored because there is so little leeway in the process. Information about doing your own color processing can be obtained from the manufacturers.)

Chapter 10 discusses methods of printing both black-and-white and color film in the traditional darkroom to express your vision in the most personal manner. Chapter 11 concentrates on the digital workflow from image capture to printing. I recommend that everyone read all four chapters, even if your approach is strictly film or digital, because they provide important insights into how the photographic process unfolds. Such knowledge is never useless.

This is the look of a typical negative under common lighting conditions. You can see density on the negative throughout the image, with no area so dense that it is impossible—or even very difficult—to print.

Figure 8-1. Negative of Stairway to Cittá Alta, Bergamo, Italy

In the 1940s, Fred Archer and Ansel Adams first developed the zone system of exposure as a means of making an exposure in a scientifically accurate manner. It is fully applicable to both black-and-white and color. The explanation that follows is expressed in terms of black-and-white tonalities; for readers interested exclusively in color, please think in terms of how these tonalities translate into colors on the color sphere (Chapter 6). After the explanation is complete in terms of black-and-white, the chapter concludes with specifics on how the zone system applies directly to color.

I’ll explain the first part of the zone system—exposure of the film—by meshing two concepts: first, how film reacts to incoming light when the shutter is open; and second, how light meters give an exposure reading.

A Brief Overview

There are only two things that can be done with a negative or transparency. First, it can be exposed; second, it can be developed. That’s it! There’s nothing more to it.

When you expose film, you can use greater or lesser amounts of exposure. That’s the limit of your control (except for changes brought about by filtration, which can alter the relative brightness of objects). In the next chapter, you’ll see that when you develop black-and-white film, you can reduce the scene’s inherent contrast (by reducing the normal development time); maintain it (by developing for the normal development time); or increase it (by extending the normal development time). Development of color film will not be explored, since it does not allow significant changes in contrast.

Film’s Response to Light: Building the Zone System

What happens to a negative when it is exposed to light? The camera lens focuses light from the scene onto the film, and it is sensitized in proportion to the amount of light that hits it. Those areas receiving the most light are sensitized to the greatest extent; those receiving the least light are sensitized to the least extent. Later, when the negative is developed, the areas sensitized to the greatest extent become the darkest, or “densest”, portions of the negative; the areas least sensitized become the lightest, or “thinnest”, portions of the negative.

Some portions of the negative may receive so little light that they are not sensitized at all. The unexposed edges of the film fall into this category, as do all portions of the film within the exposed area that are “below threshold”, i.e., areas that show no density in the developed negative except for the negative material itself, the so-called “film base fog” density. We will call all such subthreshold areas Zone 0.

There may be an area within the image space receiving just enough light to produce visible density in the developed negative, the so-called “threshold level”. We will call this developed density Zone 1. Zone 1 is an easily perceptible density, yet very thin. If you look at a portion of a negative and have to scratch your chin wondering whether or not there is density, we won’t consider it Zone 1. Only if the density is obvious, although light (thin), will we call it Zone 1.

If we were to double that exposure, the same area would receive twice the sensitization and the developed negative would show greater density. In a “normally” developed negative, we will call the density of that area Zone 2. (This is the temporary gap in the explanation referred to at the start of this chapter; the exact definition of “normal development” will be explained in Chapter 9. Here, it’s not critical to be specific about the term, so please read on.)

Now, if we again double the exposure, the Zone 2 area would receive double the sensitization, which we call Zone 3 sensitization, followed by greater density in the developed negative. Continuing to double the exposure, we obtain Zones 4, 5, 6, 7, and onward. Each successive zone represents a doubling of exposure from the previous zone and a corresponding increase in developed density (Figure 8-1).

Of course, since each zone above the Zone 1 threshold represents a doubling of exposure, those zones can be reached by successively doubling the amount of light within the scene while using the same exposure. Thus, we can obtain progressively higher zones either by doubling exposures via the lens apertures (the f/stops) or shutter speed, or by doubling the ambient light levels.