I am in the process of trying to do some film tests according to the Zone System in 35mm so I can apply it to my LF endeavor (starting cheap). I think understand the concept - Find the correct film speed that gives you detail in Zone 3, then find the development time that gives you good detail in Zone 8. Then it all got turned on its ear when I was reading a thread at P.net and someone mentioned Barry Thornton's "Edge Of Darkness". He sais that for depending on the brightness of the scene, rate the film at box ISO (cloudy, no shadows) and develop as recommended, and to rate the film at 1/2 box iso and decrease development by something like 20-30% (bright sun, sharp shadows). I thought that film testing was to give you the film's speed, regardless of the light outside! Is his vernacular just another way of deciding on exposure and N minus development for scenes that have a long exposure gradient for "non-zonies"? I'm trying to wrap my head around his use of box ISO for cloudy scenes and normal development though. It seems that film is always slower than its box ISO.....
Thanks again,
Tim
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