Red/purple staining on PyrocatHD developed negatives

[_tf_]

About a month ago my PyrocatHD (1+1+100 @ 20C) developed negatives (Fomapan 100) started showing red-purplish stains. I am using the Stearman SP-445 tank, and the stains are on the non-emulsion side of the sheets at the locations where there is an open space in the film holders (i.e., where liquid gets potentially trapped between the two sheets), most pronounced at the top of tank and one side, but in some cases running the length of the hole in the holder, and at times also at other places where there is a void behind the sheet. The nature of the stains makes them difficult to capture on a photograph, but this scan makes it clear:
Gundlach No. 2 Verastigmat lens test by tthef, on Flickr

The pronounced bright spot in the top right is caused by the red stain on the back of the negative and corresponds to the location of the hole in the SP-445 holder; there is a less noticeable one to the left of that and another that is not visible on the scan further to the left, again corresponding with the other holes in the holder.

I have stumbled on this thread, that shows what I think is the same issue, but on 120 film, https://www.photrio.com/forum/thread.../#post-2442055, and the stain is very clear there, more so I could capture on my sheet film (mine is slightly more toward red in tone), but the thread did not come to any useful conclusion.

I am fairly certain it's not a problem with the film itself, I have developed quite a lot of Fomapan 100 in PyrocatHD without issues, some of it from the same box of film. I suspect this is something to do with the staining process of PyrocatHD and the fact there is a small volume of liquid trapped in these locations that I imagine is not much replenished during agitation. I wonder if anyone has any idea if something/what in the PyrocatHD chemistry could cause the stain going read-ish, particularly if this could be due to failure of solution B (I think I mentioned elsewhere on the forum the powder in the B bag appeared to be contaminated, and the solution was not clear to start with, and I think is getting darker; I am going to mix a fresh one, unfortunately I have also recently changed to using acetic acid for stop instead of ilfostop, and started using 1% sodium sulfite to speed up washing, and I can't remember if the stains first appeared before or after this change, so I have more variables to eliminate by simple trial and error.)

Also, I would be interested in any suggestions about what to try to remove the stain; it's on the surface of the substrate, and can be scraped off with a scalpel, but that damages the substrate too much to be practical. I have tried alcohol, nafta and gamsol, but none makes any effect. I now I have quite a few sheets to experiment with, and a couple I would love to be able to fix (I initially thought these were finger prints, so first went for more hand washing and then using gloves to handle the sheets ... ).

[Doremus Scudder]

Your stain is most likely residual anti-halation dye or even sensitizing dye. It ranges from pinkish to magenta to blue depending on the exact dye and the residual concentration.

A few-minute soak in a weak alkaline solution like bicarbonate or carbonate and then a good wash (15-20 minutes) should remove it.

Doremus

[Michael R]

I would first try washing/soaking the affected sheets in a fresh 2% sodium sulfite solution in an open tray. This *might* help dissolve the dye. Since it is on the base side it is likely anti-halation dye. It is unlikely to be a problem with either the film or the developer. A problem with Pyrocat B seems very unlikely in this case.

Increased agitation in this tank may or may not help give better circulation of chemistry behind the sheets of film (which is almost certainly the problem). Note there have been various iterations of the film holders in this tank, in attempts to reduce the likelihood of things like this happening.

[Mark Sampson]

When I was using T-Max 100 (a film notorious for its pink dye), I found that an after-bath (post-fixer, pre-wash) in a weak Kodalk solution washed the dye away.
Kodalk (note the L in the name) is also known as Balanced Alkali or, I believe, sodium metaborate.

[_tf_]

Thank you everyone for your suggestions. I can confirm that resoaking the sheets in sodium sulfite clears these stains in just a couple of seconds, so I think I need to agitate vigorously during the time the film is in the sulfite to avoid this issue in the future.

[JLNims]

Thanks for posting! Although I had nothing to do with it, it's always good to observe and learn!

~Jeff

[Jim Noel]

First I would wash the device you are developing in with a strong solution of Sodium Metaborate, or sodium sulfite. Rinse thoroughly.
If washing it doesn't cure the problem, throw it away and use a flat bottomed tray.