In most cases, a 200 ISO film is the good compromise. Sensible enough to be used in moderate low light situations, but slow enough to keep a reduced depth of field in order to draw attention on the subject. Unfortunately, if emulsions makers offer a good choice of ISO 200 color negative films, there is no ISO 200 B&W films.
I love Delta 100 and though I prefer Delta 400 to other 400 films (but Tri-X is not that far away), I find its sharpness disappointing for the kind of pictures I do (I find my pictures disappointing by themselves too, but it's another matter). So I tried to push Delta 100 to 200 and here are the results I got from the first roll.
First test
Step 1 process Delta 100 at EI 100
for 135 filmDelta 100 at EI 200
for 135 filmDeveloper Kodak Xtol 1+1
Kodak Xtol 1+1
Temperature 24° C
24° C
Agitation First minute then 5s /mn
First minute then 5s / 30s
Time 9 mn
11 mn
Result Excellent tonality
Very fine grain
Excellent sharpnessSlightly too contrasty, tonality a little bit too short in low lights, whites are very dense.
Grain is a little bit coarser but sharpness is almost as good.Verdict Go on like that! Agitate less.
So I'll have to refine the process. Note that I have to develop a Delta 400 film exposed at 200 to see if it could be a viable alternative. More on these tests later. In the meantime, here are two pictures taken in those conditions:
Delta 100 at 200, Step 1 process, Leica M2, current Summicron 50 mm, 1/30 at f/2.8
Delta 100 at 200, Step 1 process, Leica M2, current Summicron 50 mm, 1/1000 at f/5.6
Second test
Step 2 process Delta 100 at EI 200
for 135 filmDeveloper Kodak Xtol 1+1
Temperature 24° C
Agitation 30s then 5s / mn
Time 11 mn
Result Stronger contrast than at EI 100.
Grain is a little bit coarser but sharpness is almost as good.Verdict OK

Delta 100 at 200, Step 2 process, Leica M4-P, current Summicron 50 mm, 1/250 at f/11
This time, it seems good. So Delta 100 is usable at EI 200 if we can accept a little loss about grain. Micro-contrast is even stronger, so accutance is preserved. In a word, Delta 100 is a very good 200 ISO film.
Well, news are not that good. At IE 200 (6mn 30 s in Xtol), Delta 400 is weak. Grain seems bigger than at IE 400 and accutance is the same (not surprising, you may say). For now, it's not a solution.
© Jean-Claude Berger, 2001