I've been going through the process of zone system testing for Ilford FP4+ 125 4x5. I'm using Ilfotec DDX at 75 degrees (because I live
in Arizona). I develop in a Jobo CPP3 using a 3010 Expert Tank. I pre-soak for 5 minutes based on Jobo's recommendations, use 300
ml of DDX, and equal amounts of Ifostop (10 seconds) and Rapid fixer (3.5 minutes). All density measurements are being made with an
X-Rite densitometer.
My film speed test gave me a .11 density at EI 100 and a .09 density at 125. This was based on using the manufacturer's recommended
development time of 8 minutes for the 75 degree temperature. Since they're both so close to .10, I chose EI 100 as my go forward speed
taking Adams' recommendation of using the higher of the two close numbers.
Moving on to the N development test. I made three identical zone VIII exposures with accompanying blank exposures using the same
setup used for the film speed test (full frame gray card focused at infinity in open shade). I'll cover the results of each below.
1. Developed the first pair using the exact same procedure I did for the film speed test - 8 minutes at 75 degrees - my density minus film
base + fog was 1.54. Because I'm using a diffusion enlarger, I'm shooting for 1.25 - 1.35. So I'm obviously too high using manufacturer's
recommendation.
2. Developed the second pair reducing development time by 20% which was 6 minutes 24 seconds at 75 degrees - my density minus
film base + fog was 1.47. Still too high.
3. Given the relatively low drop in density between trials 1 and 2, I took the third pair down to 5 minutes 20 seconds (the same time I use
for HP5+ in DDX by the way). In this case my density came out to 1.40. Still too high.
So now I'm getting concerned that to get to between 1.25 and 1.35 for normal development the times are going to be below 5 minutes
which I've heard is not recommended in most cases. So I have several questions:
1. Am I going overkill in trying to get down to that density range? I print exclusively on variable contrast paper (Ilford RC) and if I
shouldn't be obsessing over 6 hundredths of a density measurement I'll stop.
2. Is the higher 75 degree temperature speeding up development too much to enable me to get to these densities without risking
development of the shadows?
Any other thoughts about what I might be doing wrong. I've tried to be precise in my descriptions, so let me know if there is something
that I'm missing.
Thanks in advance.
