What is Zone System?

Zone System is a photographic technique for determining optimal film exposure and processing time. It helps you to create consistent negatives and that way also makes the printing much more easier. Even though it was originally designed for black and white film, it is also applicable to color, both negative and positive, and even to digital photography. Zone System was developed around 1939-40 by Ansel Adams and Fred Archer. It's based on the late 19th century sensitometry studies of Hurter and Driffield.

What does all the zones mean? Zone 0 is maximum black. Zone I is black with slight tonality, but no texture. Zone II is black with first suggestion of texture and with deep tonalities. Zone III is black with adequate texture. Dark shadows should be placed here. Zone IV is gray. Shadows in light skin and in landscapes should fall here. Zone V is middle gray (18%). Dark skin and clear north sky should be placed here. Zone VI is gray. Light skin, diffused skylight or artificial light should fall here. Zone VII is white with full detail. Very light skin, light gray objects and snow with acute side lighting should be placed here. Zone VIII is white with texture. Highlights on light skin and textured snow should fall here. Zone IX is white without texture. Snow in flat sunlight should fall here. Zone X is pure paper white. Specular highlights and light sources should fall here.

How to use the Zone System? Find a scene you want to photograph. Meter darkest and lightest part of the scene with your spot meter. Figure out how many stops are between them. Information is needed for deciding the right processing time. Meter the darkest part again. Spot meter shows everything as Zone V, so we need to stop down 2 stops to place the darkest part of the scene to Zone III. Finally, expose the scene.

Now we need to determine the right processing time. 5 stops means normal processing. 4 stops means +1 stop from normal processing. What it really means is that we need to multiply the normal processing time by 1.4. 3 stops means +2 stops from normal processing. What it really means is that we need to multiply the normal processing time by 1.9. 2 stops or less means that it's not worth of wasting your film. 6 stops means -1 stop from normal processing. What it really means is that we need to multiply the normal processing time by 0.7. 7 stops means -2 stops from normal processing. What it really means is that we need to multiply the normal processing time by 0.6. 8 stops or more means that it's not worth of wasting your film. If you are shooting t-grain film, then the processing times will be a bit different for you.