Quick reality check. I just wanted to compare notes with someone who has tried this film.
I've shot a couple of rolls of Efke 100 35mm (souped in D-76 1:1) and I'm having a problem with the exposure. While other 35mm B&W films that I shoot seems to expose at their marked ISO, Efke 100 seems to want about a stop and a half more exposure to give any decent shadow detail. Also, when I process Efke 50 rollfilm, the presoak pours out dark from the dissolved antihalation backing while the 35mm comes out clear. There seems to be bigger difference in these films than just speed and size.
While I have not personally shot any of the Efke PL 100 film, I did have the opportunity to read densities on some Efke negatives that Jim Shanesy (C6H6O3) sent to me. The film does build density very well for alternative process and Azo. I believe that Jim had rated the film at less then the mfg speed (possibly 50). The low densities of these negatives indicated that the film was over exposed at the speed that Jim had rated the film.
The film that Jim sent to me had been developed in ABC Pyro and also Pyrocat. I could make a case that the developer that you are using is not as active as what we use when developing negatives to a higher DR. Therefore it may very well be that EI 50 is appropriate for the developer that you are using. (As one develops to a higher DR the film speed actually will show an effective increase.)
Metering and Zone placement are equally as important as the EI that one assigns to a film. I don't know what you are using as a meter and how involved you are in exposure calculations.
I have ordered some 4X5 Efke and should have more pertinant personal experience a little later.
This summer I used a mixture of PL100, APX 100 and FP4+: My last 4x5 APX, my first 9x13 PL100, and FP4+ in 5x7".
I can see no difference in shadow density on these three films developed in Pyrocat-HD by inspection. I have no densitometer and have not tested "properly", just shot similar scenes with all films at the same exposure. I judge my shadows when trying to print the negatives...
PL100 also contracts very well in compensating developers, making it possible to get full details over a 19-stop range.
I developed two 8 x 10 Efke PL100 negatives last night in ABC pyro. I had rated the film at 100. While there is good shadow detail, the highlights are a little thin and will probably necessitate grade 3 Azo right from the gitgo. The subject matter in this case made the negatives nearly impossible to inspect. (A white stucco wall. No highlights to stand out against it.)
I'm going back to 50 for this film. I've yet to find a film that I can rate at what the manufacturer recommends for development in ABC pyro.
Try Pyrocat HD 2:2:100 with Efke PL 100 8x10 at the rated speed of 100. You will have no problem with both highlights and shadows. For a normal SBR of 8 try 9 mins 15 secs.
My only experience with Efke 100 has been with R100 (120 version) exposed at 100 and developed in Neofin Blau. Resolution was very crisp and grain well within acceptable bounds - tighter and finer than Rodinal.
The speed appears to be right at 100. I got good shadow detail and excellent midtones. It appears to have many of the qualities I enjoy in 120 APX 100.
The presoak effluent poured off a heavy dark greenish blue color. Only one shot was aimed into strongly backlit trees indicating the anti-halation treatment is probably necessary - there was some halation spillover into the margins.
You might try a roll in a developer like Rodinal, a Beutler type or something similar.
Your response was particularly helpful. I was beginning to think that I was the only one here that isn't using Pyro. For some reason at 100 everything under zone III just disappears. I definitely need to "overexpose". I am quite happy with the results in D-76 1:1, very fine grain, good sharpness and tone. A nice film to keep at least one camera body loaded with.
It's funny though, the 35mm doesn't discolor the presoak like the 120 does. I wonder how different the emulsions are?
Nah, I don't use pyro type stuff...yet. I've adopted a one-in, one-out policy and I'm not sure which of my regular developers I'd be willing to give up to try another.
I think our individual metering habits affect our results more than we'd like to admit. Then you throw in meter calibration, etc., it's a wonder any of us ever agree on anything.
Regarding the presoak, I dunno. I recently tried some 35mm "Freestyle" ISO 50 film labeled Made in England. I assumed it was Pan F+ but it doesn't look like it. The raw film stock looks much different. The negatives are similar tho'. Absolutely no color in the presoak effluent. Who knows...presoaking is mostly voodoo anyway.
With some East European films that have a blue/green antihalation dye, I find the presoak necessary, because the dye doesn't necessarily come out in the fix/wash like the magenta dye in T-Max films. I'm experimenting with PL100, but haven't had a chance to process the first exposures yet.