I have a box of Ilford Delta 100 I want to shoot this weekend and have three "dumb" 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 Barnbaum'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 the stuff wasn't right at its published 125 ISO.

2) I have two developers, Infosol-S and HC110. What are the basic differences in 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 dilution.

What has me concerned it that the dillution B from concentrate to working solution is 1:31, while dilution E is 1:47 (per the Kodak data sheet) Surely these differing 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 dilution E. Is the dilution E on tyhe Ilford Delta 100 data sheet a misprint???

THX much,

T

-- Todd Tiffan (drsarvis@hotmail.com), January 27, 2000

Answers

First, dump the HC110. Ilford believes the finest match for Delta 100 is ID11 at 1:1. Second, go out & shoot 4 identical negatives of 3 scenes & come back & process them at whatever starting time you want to try-it really isn't that important. Then fine tune with the second and third sets of negatives & you will be very, very close to your 'correct' developing time. If you don't do a basic check of exposure & development(not months of inane testing for every contingency) you will be lucky to get good results the first time out. Your water is different, as is most of what you will do, so one persons times worked out with experience & a few tests won't be the same you will get. Close maybe, but not right for you.

-- Dan Smith (shooter@brigham.net), January 28, 2000.

Todd, you will find all the developing times for almost every film @ http:// www.digitaltruth.com/ These are all recommended times so always do tests to work out what is good for you. Cheers, Scott

-- Scott Walton (scotlynn@shore.net), January 29, 2000.