THE ZONE SYSTEM
Ansel Adams developed the Zone System approach for fine control over exposure and printing – and it’s still relevant in the digital age
In 1940, Ansel Adams, along with his fellow instructor at the Art Center School in Los Angeles, Fred Archer, developed the Zone System. Photographers had long known that they could alter the contrast of a negative by changing the development time: shorter development lowers contrast; longer development raises contrast. Adams and Archer were the first to quantify this and relate it to exposure. They created a precise procedure for evaluating the light and dark values of a scene, visualising the finished photograph, exposing the negative, and developing that negative to hold the contrast the photographer visualised.
This system is still valid when using black-and-white film today, but how does it relate to digital photography? There’s a fundamental rule in digital imaging: it’s easy to increase contrast, but difficult or impossible to decrease it. So, if an image looks flat, it’s easy to add more punch later in software. But if the scene has too much contrast – if it exceeds the dynamic range of the camera – then part of the image will either be pure black or pure white.
If you need detail in both highlights and shadows in a high-contrast scene, you’re not totally out of luck as you can combine two or more separate exposures to expand the dynamic range [see page 27]. But let’s assume your contrast range is fixed. Is the Zone System still useful? Yes, as a way of setting an exposure quickly and accurately.
To use the Zone System you have to have a spot meter and use the camera in manual mode. The spot meter can be handheld or built into the camera, but either way, the smaller the spot, the better.
I have found that the Zone System is invaluable in colour photography, primarily in relation to exposure, but of course its application poses very subtle considerations. Ansel Adams