Editing Zone System (section)

=== Additional darkroom processes ===

Adams generally used [[selenium toning]] when processing prints.  Selenium toner acts as a preservative and can alter the color of a print, but Adams used it subtly, primarily because it can add almost a full zone to the tonal range of the final print, producing richer dark tones that still hold shadow detail. His book ''The Print'' described using the techniques of [[dodging and burning]] to selectively darken or lighten areas of the final print.

The Zone System requires that every variable in photography, from exposure to darkroom production of the print, be calibrated and controlled. The print is the last link in a chain of events, no less important to the Zone System than exposure and development of the film. With practice, the photographer visualizes the final print before the shutter is released.