So I have been shooting Fomapan 100 for a few years now but recently changed to Fomapan 200 and I would suggest the Pyrocat may be what requires further investigation.
When I first saw this thread and the Magenta cast I immediately recognized something that has happened to me. To confirm I went though my archive of negs to see which ones have a magenta cast, according to my notes the only Foma 100 Negs I have with the cast are all developed in Pyrocat HD 1+1+100 for 10mins @20deg (curiously the volume isn't listed) in a Jobo CPE Plus. I have other negs developed in ID-11 and Fomadon Excel (Xtol clone) and all of these have the regular neutral base that I would expect. The Magenta ones still managed to be contact printed however it probably helps that I needed a high level of contrast adjustment for the images in this case, could be quite the problem if you are going for low key however I do not have an example of this.
Interestingly none of my Fomapan 200 images have this magenta cast even with the same process. What I suspect has happened in my case is I have done something wrong with the minimum amounts of pyro required as the strongest examples I can find for this are all on 4x5. As I switched to Fomapan 200 about a year ago I don't have any 100 around to do further testing with. I would suggest to anyone who is serious about getting to the bottom of this, start by trying to replicate with pyrocat and then seeing if you can replicate with another developer. If I would have to guess try going below minimum valuers of chemistry for the amount of film being developed however this is just a guess on my part.
I hope this can help and gets us a little closer to the truth.
When I first saw this thread and the Magenta cast I immediately recognized something that has happened to me. To confirm I went though my archive of negs to see which ones have a magenta cast, according to my notes the only Foma 100 Negs I have with the cast are all developed in Pyrocat HD 1+1+100 for 10mins @20deg (curiously the volume isn't listed) in a Jobo CPE Plus. I have other negs developed in ID-11 and Fomadon Excel (Xtol clone) and all of these have the regular neutral base that I would expect. The Magenta ones still managed to be contact printed however it probably helps that I needed a high level of contrast adjustment for the images in this case, could be quite the problem if you are going for low key however I do not have an example of this.
Interestingly none of my Fomapan 200 images have this magenta cast even with the same process. What I suspect has happened in my case is I have done something wrong with the minimum amounts of pyro required as the strongest examples I can find for this are all on 4x5. As I switched to Fomapan 200 about a year ago I don't have any 100 around to do further testing with. I would suggest to anyone who is serious about getting to the bottom of this, start by trying to replicate with pyrocat and then seeing if you can replicate with another developer. If I would have to guess try going below minimum valuers of chemistry for the amount of film being developed however this is just a guess on my part.
I hope this can help and gets us a little closer to the truth.