Any Thoughts On What Has Caused This

Well I have to admit I use a water stop these days for film, but I check my fixer baths regularly. Until I moved abroad I always used a stop bath, you keep re-using it until the pH changes. I always use stop bath for prints, it's very cheap but then I have about 10 litres of glacial acetic acid which cost me nothing so mix my own.

Ian
 
The gap between the backs of the film is quite small in the Stearman tank. It's still small with the new skeleton holders. I wonder if this has anything to do with it. Could Ian's gentle agitation pattern have left an undisturbed residue that became entirely exhausted. This doesn't quite explain the neatness of the pattern.
 
David M said:
The gap between the backs of the film is quite small in the Stearman tank. It's still small with the new skeleton holders. I wonder if this has anything to do with it. Could Ian's gentle agitation pattern have left an undisturbed residue that became entirely exhausted. This doesn't quite explain the neatness of the pattern.
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Again, this could also be a possibility. I know someone who did experience like an online from the inner supports in the skeleton holders on developed negatives. I will try to increase the speed of the agitation from now a little more to try and keep the liquid moving.

As a matter of interest, with the SP-445, holding the tank in both hands, I agitate towards me in a 360° pattern
 
As mentioned previously, the acid stop bath protects and extends the life of the fixer compared to using water as a stop.

Mike
 
Ian-Barber said:
I know someone who did experience like an online from the inner supports in the skeleton holders on developed negatives.
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I experienced this with the v3 holders. I've now returned to using the original v1 holders.
 
You might try agitating sideways. Agitation dislodges the very thin layer of used chemical from the surface of the film and replaces it with fresh solution. Very gentle agitation might not fully achieve this as a certain amount of turbulence is needed to mage this happen. I'm not sure of the purpose of gentle agitation. It would be very difficult to dislodge the film in the Stearman tank. I did meet someone who agitated like a cocktail shaker, which seemed to work without problems.
I have the original solid holders and when the film is wet, I can see marks from the ridges on the back of the film, but they seem to vanish after drying, I have drilled a hole in the middle and cut some thumb notches to help remove the film.
 
Wouldn't extreme agitation cause a build up of contrast to quickly or is that more a case of how often you perform the agitation
 
Ian-Barber said:
Wouldn't extreme agitation cause a build up of contrast to quickly or is that more a case of how often you perform the agitation
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Agitation technique will change contrast, given all other parameters being the same. Also, I've never tried it, but I'd guess that too turbulent of an agitation cycle with the SP-445 might cause the film to dislodge from the small clips that hold the film in the holder; that wouldn't be good.
 
Yes, Alan is right. Too little agitation risks insufficient development with low contrast and too much will generate more contrast and density. I suppose we adjust the time and agitation to suit. Development in tubes gives continuous agitation and the usual advice is to reduce the time by about 15%. I don't recommend the cocktail-shaker method; it's micro-turbulence that we need. I'm visualising that very gentle inversion could give laminar flow over the film surface. With the SP-445, a really good shaking might push the lid off. You can knock the film out of its runners with the Combiplan tank, if you agitate front-to-back. (But only once!)
However, we believe that we now know the original problem only happened with well-used fixer, which showed up the problem. Fresher fixer seems to have done the trick.
Remember when we thought the Zone System would solve all these problems?
 
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