20060830 Wednesday August 30, 2006

Zone System and Exposure Meters

Here‘s the basic premise of the zone system. Your tonal range is separated by 10 stops ranging from pure white to pure black in a printed picture . By performing a set of test shots at the rated speed of the film, you can more easily visualize what the tones look like. Most important is the reference zone, Zone V. Zone V is what your exposure meters are calibrated to reproduce. That means if you point the meter in shadows, the shadows will be exposed to render medium gray. As a result the highlights will likely fall outside the usable range of the film.

Ah, but here is where things fall into place. The usable range of film would be zones II through IX, with zones III through VIII having full detail. You always want the darkest part of the picture where you want full detail to be in zone III. Then using your spot meter you can find out where other parts of the picture happen to fall. To expose the shadow detail in zone III, you spot meter the shadow and drop the suggested exposure two stops. It‘s not a hard and fast rule, but it provides you with better tools to interpret what your meter is telling you.

Of course it still works with color film, although it‘s easiest to think of tones in terms of black and white. The bottom line is that once you‘ve calibrated your system to middle gray, you have a wonderful tool at your disposal. And there‘s the rub. How do you calibrate your exposure time without a densitometer? Most of us enthusiasts don‘t have the tools at our disposal to perform the tests to make the system really work for us. There is a way to do it using an enlarger and prints, but if your workflow stops with a scanner like me, what do you do? I‘ll have to figure something out. I may have to buy a used densitometer to make it worth my while.

(2006-08-30 22:28:22.0) Permalink Trackback


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