Q Can the Zone System be used with color film

A: In general the answer is yes, and in many ways certain inherent characteristics and limitations of color films make the Zone System an even more important tool.

The rules of exposure apply as much to color film as they do to black-and-white film. On the other hand, color materials present you with special problems of which you should be aware. First, the range of subject contrast that can be recorded on color reversal films (otherwise known as chrome, transparency, or slide films) is relatively narrow when compared with color negative or black-and-white films. The effective range of detail in a properly exposed and processed color negative can be between Zones II and VIII. With transparency films the range is between Zones III and VII. Slide films are very intolerant of exposure errors (they have limited exposure latitude).

If your exposure is more than one-third of a stop under the correct placement of Zone III, the whole image will be too dark. This means that in general you will get better results using color-slide film in situations where the contrast is not too great; indoors with flash or outdoors on slightly overcast days, for example. The accuracy and reliability of the Zone System of exposure can be of great advantage when you are shooting color films.

The second problem is that if color film is given more or less development than the amount predetermined by the manufacturer, you run the risk of getting inaccurate color in the resulting slide or negative. Overdevelopment causes the images to look warmer (more red); underdevelopment results in cooler pictures (more blue). This shift in color balance can be corrected to some degree when color negatives are printed.

Underdevelopment also causes the black areas of color slides or prints from color negatives to be "incomplete," meaning that the black areas will be rendered as a muddy dark gray with a noticeable colorcast. One result of this effect is that there is no simple way to control the contrast of color films without affecting the color rendition. This means that you may have to adapt the way that you expose color film when subject contrast is greater than the effective range of the material you are using.

For example, if you are shooting a very contrasty subject, a snow scene with dark foliage for instance, you may have to expose for the highlights and allow the shadows to fall where they will. This could mean metering the snow and placing the reading on Zone VII or VIII for color negatives or Zone VII for color-slide films. The foliage will probably print as relatively dark silhouettes, but the overall impression of the image should be acceptable. If possible, you could use an electronic flash to add more light to the darker areas.

Color negative films are self-masking, which means that the density of the highlight areas is restrained as they develop. This essentially allows the shadows to "catch up," giving you relatively more detailed dark areas without blocked-up whites. Color negative films can be overexposed by as much as three stops and underexposed by one stop, and the negatives will still be printable. Color-slide films don't have these advantages. Because of this and their more narrow contrast range, color transparency films require more careful control.

One major advantage of understanding and using the Zone System is that it gives you a reliable way of measuring subject contrast and exposing accordingly.

In commercial studio and location photography, it is often necessary to use longer or shorter development times to make small, precise corrections of the overall density and contrast of your negative or chrome. Usually Polaroid materials are used to proof setups. Contrast and exposure manipulation is done with extra lights or reflecting fill-cards. If more corrections are needed, many of the better color labs will custom process color films if you know the practical limits of the materials and how to explain what you want to the technicians.

To color labs, pushing and pulling film means, respectively, increasing and decreasing the development time. Instead of "zones," they are more accustomed to speaking in terms of "stops." Thus "pull this film one stop" means "please reduce the development time of this roll by enough to give me one zone's worth of Contraction."

The following is a list of some color films and the amount of contrast control you can ask a lab to give you and still get acceptable results. N.R. means "Not Recommended."

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