To repeat something I wrote in another thread, the issue of SBRs of less than 5 is for all practical purposes a mute question for photographers contact printing with in-camera ULF negatives on AZO #2 and many alternative processes, including albumen, carbon, kallitype, platinum and palladium and Vandyke. These processes have log exposure scales on the order of 1.5 to 2.2 and even normal SBR of 7 require negatives with a CI of .75 and higher.
In reality very few films available in ULF have enough expansion capability to reach even SBR 5 when the CI even for normal SBR is so high. Ilford FP4+ and Efke PL 100 just make the grade but nothing else comes close.
What to do if you print with alternative processes with in-cameras ULF negatives? Well, no point to obsess about exposure technique for potential SBR values below 5 since the available films won’t allow it anyway. The only option is to expose the film at the lowest SBR value your film/developer combination is capable of, which you would have determined from previous tests, and then use process controls to give the contrast desired on the print.
As for the broader issue of Zone System versus BTZS, this is pretty much a non-issue for me. I use them both, depending on conditions. In fact, before I discovered BTZS I had been using Zone System for the better part of two decades. At this point, however, I will say that I prefer BTZS for about 90% of my work. But there are a few conditions where Zone is easier to use. If you have actually used both in the field you will, or should, understand this.
Last edited by sanking; 04-16-2005 at 01:04 AM. Click to view previous post history.