I have a box of Ilford Delta 100 I want to shoot this weekend and have three "du mb" questions (and remember there are no stupid questions, just stupid people):
1) Any idea what the "true" ISO speed is? What I mean is what do I have to rate it at to get a zone 1 value with 4 stops under what the meter says (per Bruce B arnbaum's film test procedure). I conducted this test with FP4 Plus, sent it to the local lab which must be running normal T-Max devo, and I'll be darned if th e stuff wasn't right at its published 125 ISO.
2) I have two developers, Infosol-S and HC110. What are the basic differences i n results? Any recommendations (I'm using an HP combi 6 sheet tank)?
3) I look at the Ilford data sheet for the Delta 100 and it gives the 68 degree devo times for Delta 100 (EI of 100): Dilution B for 6 minutes; Dilution E for 7.5 minutes. The 50 EI is about the same realtive time difference for each dilu tion.
What has me concerned it that the dillution B from concentrate to working soluti on is 1:31, while dilution E is 1:47 (per the Kodak data sheet) Surely these di ffering concentrations would give more of a time spread than what's published. Furthermore, the data sheet on FP4 Plus mentions only dilutions A & B for HC110, and Kodak's data sheet for their films (T-Max and Tri-X) doesn't even mention d ilution E. Is the dilution E on tyhe Ilford Delta 100 data sheet a misprint???