Rick Olson
Member
Hello,
I was developing some Ilford HP-5 and Arista Ultra 400 film (120 size) today and had an issue with uneven development. My equipment is a Paterson tank that allows use of two 120 plastic reels. I noticed thin bands of uneven development (thinner) along the entire length of the film that would be upright when loaded on the reels in the tank. Both the Ilford and Arista had these marks.
Process:
6 minute pre-soak (water)
12 minutes developer (Pyrocat-HD - 1000 ml (500 ml per 120 roll))
1 minute water stop
4 minutes fix
wash, photo-flo, dry
My reasoning was that this might be caused by the large amount of foam I saw once I started development and checked, which might be lodged in the reels during the agitation stage, then stuck between the film emulsion and reel when returned upright.
To test, I shot two of the exact same types film and instead of just using a static water pre-soak, I agitated and made 3 rinses to remove as much of the foam residue as possible. I processed as noted above and finished fixing, then inspected. Same problem!!
Can this be resolved by using more developer? Perhaps, reducing the amount of chemical inversion activity that might be causing the formation of foam and bubbles. What about introducing an anti-foam agent during the pre-soak before development? Is there such a thing?
Any assistance would be appreciated.
Thanks,
Rick
I was developing some Ilford HP-5 and Arista Ultra 400 film (120 size) today and had an issue with uneven development. My equipment is a Paterson tank that allows use of two 120 plastic reels. I noticed thin bands of uneven development (thinner) along the entire length of the film that would be upright when loaded on the reels in the tank. Both the Ilford and Arista had these marks.
Process:
6 minute pre-soak (water)
12 minutes developer (Pyrocat-HD - 1000 ml (500 ml per 120 roll))
1 minute water stop
4 minutes fix
wash, photo-flo, dry
My reasoning was that this might be caused by the large amount of foam I saw once I started development and checked, which might be lodged in the reels during the agitation stage, then stuck between the film emulsion and reel when returned upright.
To test, I shot two of the exact same types film and instead of just using a static water pre-soak, I agitated and made 3 rinses to remove as much of the foam residue as possible. I processed as noted above and finished fixing, then inspected. Same problem!!
Can this be resolved by using more developer? Perhaps, reducing the amount of chemical inversion activity that might be causing the formation of foam and bubbles. What about introducing an anti-foam agent during the pre-soak before development? Is there such a thing?
Any assistance would be appreciated.
Thanks,
Rick