DREW WILEY
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- Jul 14, 2011
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If one has a tiny budget, and just wants to learn Zone System basics or determine "personal" film ASA's, then simple visual densitometry might be all you ever need for black and white work. Almost every photographer already has a light box. Or you could substitute a smartphone if it has a constant light setting for a blank screen, or an illuminated reading tablet minus text. Then you need a basic 21-step CALIBRATED Stouffer strip step tablet, preferably new and not a yellowed old one; maybe
$20. Then a basic dirt cheap one hole paper punch. If the 1/4 inch holes are too big for you, substitute a smaller diameter leather punch. Then a six by six inch piece of opaque black cardboard.
Punch two holes near the center of the card about two inches apart. Then you place the black card atop the light box, preferably blocking off any extraneous perimeter light, slip your step tablet under one hole, and the selected part of your negative under the other. Slide around the step tablet until they visually match, or are so close that you can intuitively interpolate any mid densities. This method worked for decades prior to modern densitometers, even for complex dye transfer color printing applications. The original Kodak densitometers were just a fancy version of this same concept - totally visual. These still sometimes turn up for sale dirt cheap; but their very old density strips are probably now too dirty or yellowed to be trustworthy.
Slightly different topic - What jerry-rigged light-meter/densitometers can't do well at all is handle precise small differences in the low-density shadow reproduction values which define the rate of the lift-off of the toe onto the straighter line portion of the curve. This is particular interest to me because I often work with high contrast scenes and want to take advantage of all the curve real estate that I can, especially down there at the bottom. I also do very demanding curve analysis for things like color separation negative and critically matched masks.
Those improvised DIY tweaks won't do very well way up at the top either, where the density is high and tends to shoulder off. But most Zone Theory gurus try to get you to place the threshold of shadow value on Zone 3 or Zone 4 just hedging their bets, and then up to around Z 8, plus spare change. So an outright official densitometer isn't necessarily required for that kind of "good enough for government work". Even visual densitometry will be adequate. I don't know why AA thought he could restrict the universe to just eight zones when Moses allowed ten.
$20. Then a basic dirt cheap one hole paper punch. If the 1/4 inch holes are too big for you, substitute a smaller diameter leather punch. Then a six by six inch piece of opaque black cardboard.
Punch two holes near the center of the card about two inches apart. Then you place the black card atop the light box, preferably blocking off any extraneous perimeter light, slip your step tablet under one hole, and the selected part of your negative under the other. Slide around the step tablet until they visually match, or are so close that you can intuitively interpolate any mid densities. This method worked for decades prior to modern densitometers, even for complex dye transfer color printing applications. The original Kodak densitometers were just a fancy version of this same concept - totally visual. These still sometimes turn up for sale dirt cheap; but their very old density strips are probably now too dirty or yellowed to be trustworthy.
Slightly different topic - What jerry-rigged light-meter/densitometers can't do well at all is handle precise small differences in the low-density shadow reproduction values which define the rate of the lift-off of the toe onto the straighter line portion of the curve. This is particular interest to me because I often work with high contrast scenes and want to take advantage of all the curve real estate that I can, especially down there at the bottom. I also do very demanding curve analysis for things like color separation negative and critically matched masks.
Those improvised DIY tweaks won't do very well way up at the top either, where the density is high and tends to shoulder off. But most Zone Theory gurus try to get you to place the threshold of shadow value on Zone 3 or Zone 4 just hedging their bets, and then up to around Z 8, plus spare change. So an outright official densitometer isn't necessarily required for that kind of "good enough for government work". Even visual densitometry will be adequate. I don't know why AA thought he could restrict the universe to just eight zones when Moses allowed ten.
