If you have been around photography for very long a couple quick observations come to mind. First, things just sound complicated and in reality they really are not. Math is involved so that puts a certain distribution of people in the tank all on its own! My goal in this article is to show beginning black and white film photographers a way then can produce good quality black and white negatives when printing in the darkroom. Entire books have been written on some of these concepts so keep in mind that I am trying to distill over 100 years of knowledge into a simple, easy to apply set of tips. If you send your film out for development then you are left at the mercy of your lab.
We are going to discuss how to properly expose for shadow detail in your scene and make the appropriate adjustments on your meter/camera. By employing this simple technique and then following up with some simple techniques in the darkroom you will get good quality results.
Rating Your Film
Based on the subject matter in this article I have to assume you don’t know how to properly test your film for you own personal EI (exposure index) rating and you have no working knowledge of the zone system. The best advice I can give a black and white film photographer that is not using a scientifically tested film and developer combination is to rate your film at half the box speed and then develop for a little less time than the manufacturer data sheet instructs. For example if you are using T-Max 100 then rate it at EI 50. If you are using Tri-X 400 then rate it at EI 200. If the manufacturer data sheet says to develop at 6 minutes then develop for 5 or 5 1/2 minutes. Something in the range of 15% is the rule of thumb that I would suggest. In effect you are doubling the light to your film by cutting your ISO in half and then you are compensating two stops because our meters read the scene in zone 5. If you refer to the illustration below you will see tone difference between zone 5 and zone 3 and my explanation should become obvious.
Calculating Your Exposure
For my style of photography I want to control my depth of field so by default I meter and think in terms of aperture priority. I use all manual cameras and use a hand-held spot meter. You may be different and just adjust as necessary. When you meter your scene with your camera or exposure meter look for an area that is the darkest area that you still would like some detail in your print (shadow detail). Since your meter measures everything in zone 5 (middle of the scale) you will need to stop down 2 full stops to get your shadows on zone 3. You can do this by increasing your shutter speed by two stops (e.g., 1/15 meter value to 1/60th new shutter speed) or if it fits your creative vision you could change your aperture from let’s say f/5.6 to f/11. In photography lingo you may have heard this referred to as “stopping down”. It doesn’t matter if you are using an internal meter on your camera or an exposure meter, you should have it set to spot metering mode.
This is also why when you photograph snow you have to go the other direction. For example, if you have some beautiful snow in your scene that has been untouched by foot prints I would probably expose at + 1 1/2 or + 2 stops. As a general rule I try and keep everything with detail between zones 3 and 8. When I shoot flowers against a black backdrop I don’t want or need detail so zone 0 is my target.
If you refer to the zone system scale below all of this will make sense.
So far you have cut your film speed in half and you have stopped down two stops from your shadow detail meter reading. Now all this is left is to release the shutter and take the picture. That is all there is to it! Since you are printing in the darkroom you will want to develop for your highlights first and then work on your shadows. This is where the old phrase “expose for your shadow detail and develop for your highlights” comes from. This is beyond the scope of this specific article, but this is why variable contrast papers and filters were such a success with black and white photographers. It is like having several grades of paper at your disposal all on the same print. You can refer to an article that I wrote on how to make an enlarged black and white print that will give you additional information on this topic.
When you self-develop your film just decrease the time of your development a little and you should be set. For example if your film data sheet says to develop for 6 minutes then something in the range of 5 minutes would work nicely or use the rule I stated above and decrease by about 15%. If you are interested in my opinion about black and white developers then you may want to read that article as well.
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