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

NPhoto - - The Zone System -

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

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