View Full Version : Fomapan 100; reciproke failure already kicking in at "fast" speeds ?

18-May-2013, 02:48
Here is something which is bugging me for sometime, and I cannot figure it out:

I have been shooting Fomapan 100 for quite some time now in 4*5, at 50 Asa, souped in Xtol (actually Instant Mytol). As we all know Fomapan has a bad reciproke failure, requiring longer exposure times at 1 or even at 1/2 seconds.

Here is my problem: even shooting at 1/8 or 1/15 seconds I think I have a reciproke problem, that is, I see quite consistently that my shadow regions are too dark, ie underexposed.

I usually spot meter the important shadow area, and place that in Zone III (so for the final exposure I open up 2 stops). When using FP4+ this method worked quite well, but with Fomapan I end up with almost empty dark areas were I would have liked more detail.

Can it be reciproke failure ie if my exposure is say 1/8 for Zone V, its 1/2 for Zone III, and 1 for Zone II, reciproke territory.

Am I barking up the wrong tree and this is a misconception ?

Exposing more would not help since my times would get even longer (I already shoot at 50 ASA) and I get a bullet poof negative in the highlights and mid tones.

I might add that my negatives print fine on grade 2 1/2 when judged by de mid and high values.

Thanks for any insight,



18-May-2013, 05:50
I don't think that reciprocity is the problem since 1/8 of a second exposure is over the whole negative not according to zone.

18-May-2013, 06:11
I'm sure someone can correct me if I'm wrong, but I believe that you are on the right track. When I do reciprocity calculations, I always factor in an N- development as well. Regardless of the speed of exposure, I believe reciprocity failure is more about how much light is gathered before a latent image is recorded. If exposing a grey card to Zone V at 1 second gets into reciprocity failure areas, so should exposing it to Zone III at 1/8th. At least that's been my assumption, and it's played out as such in my TMX negatives - when I add exposure to counter RF my highlights were blowing out with N development.

How long are you developing in XTOL? Assuming you are using a 1:1 dilution, I would think your times would be long enough to give the negative a bit more exposure and then subsequently cut development time. Usually if I add 1 stop of exposure I'll pull N-1, 2 stops pull N-2, etc.

18-May-2013, 06:58
I think it makes sense that there is still a bit of a problem with the shadows even above half a second, since the shadows get a lot less exposure than the highlights.
Fomapan 100 needs a lot of extra exposure, but I'm usually fine with shooting at 50. Maybe you should shoot even lower for those speeds and adjust development. It's always going to be personal, no matter what the charts say. If something doesn't work for you change it.

18-May-2013, 07:08
Yes. I did the calculation and stopped using the film because of this. Many (most?) of my exposures were in the 1/4 to 5 second range, right at the point where highlights are ok but reciprocity failure with that abominable film caused my shadows to severely underexposed. And when I corrected for the shadows, often getting exposures of 10s - 2.5min, my highlights were so blown out that no compensating developing could possibly save them.