I like to experiment with Push and Pull exposure/processing techniques as it applies to black and white film. My film choice for this blog post is the Chinese made, LUCKY SHD 100. This is an inexpensive local film for both 35mm and 120 and when used correctly can produce very good results. I began with pushing it to ISO 400 with very spotty results. I was getting more misses than hits. After shooting about 6 or 7 rolls this way and studying the results and checking my notes, I came to the conclusion that this film is not ISO 100, but slower perhaps closer to 50 (it should be pointed out that I did not do any serious Zone V exposure tests to accurately gauge the true speed of this film). I then began to shoot at ISO 50 and ISO 25 with far superior results. The tonal range is much wider with softer contrasts and better shadow detail. For all these shoots I used D76 stock or, for the ISO 50 and 25, at 1:3 dilutions.
On the train to Hong Kong one day all of these test results sort of made sense to me and everything became simple. I now feel that the ISO ratings on the boxes of black and white film are arbitrary. Stop thinking about your HP5 at 400 and think more about your vision. To shoot HP5 at 400 is the recommended optimal ISO setting. I am not here to argue with Ilford or claim that I know better than they do. What I’m saying is this number is a sign post, a guide. Like the famous Buddhist finger pointing at the moon, don’t get caught up staring at the finger and forget about the moon. Think of your film as an empty page or canvas, ready to receive whatever, and however, you want to inscribe or draw or paint on it.
As you begin to deviate from the recommended ISO settings, remember you may have to make changes to your developer and development time(s) to properly balance your desired final image. When I was pushing to ISO 400, I used D76 stock because I wanted a lot of punch with strong contrast and I didn’t really care about deep shadow detail. When I shoot at ISO 50 or 25, I develop with D76 at 1:3, paying close attention to my developing times and the amount of tank inversions (development time affects lows and mids, and tank inversion increases contrast).
This newly realized flexibility of tonal range, ISO and contrast has had a profound effect on me and made Zone System discipline even more important to my style. For years, I slavishly shot at the recommended settings never deviating or questioning it. I didn’t understand why you would change it, when or how. But this new understandingly has had a humbling effect. Its very easy to allow the ego to puff us up and make us think we are doing something really special. But when I gained this small moment of clarity into the bigger world of film photography and developing, I realize I know nothing…that there is so much more to learn. Pondering this doesn’t fill me with a sense of failure but of appreciation for our art and a continued desire to learn, grow and teach.