What causes uneven sky density when developing 4x5 sheet film in an SP-445 tank?
Asked 11/3/2018
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2 answers
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I’m getting uneven density in skies on Ilford Delta 100 4x5 negatives developed in an SP-445 tank. I had a similar issue years ago with tray development, but tank processing seemed to solve it for over 100 sheets when I was using D-76. The problem has recently returned, and it seems to coincide with switching to Adonal.
Current process:
- Developer: Adonal 1:50, 14 minutes at 20°C
- Agitation: 4 inversions once per minute
- Stop: water, 1 minute
- Fixer: fresh, 4 minutes
- Wash: 4 fill-and-dump cycles, rotating 5x, 10x, 20x, 40x
- Photo-Flo: 30 seconds
What is the most likely cause of this uneven development, and should I change my agitation method?
Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0
Photography Stack Exchange contributor
7y ago
2 Answers
3
Make sure that you're agitating correctly. Inversions should be somewhat abrupt. I invert five times in five seconds every thirty seconds (i.e. five seconds of agitation, 25 seconds of sitting, then repeating). Ten seconds of agitation at the start of every minute should work pretty much as well; I know some home processors use this style instead. I've never had uneven development of film, so I've not tinkered with my agitation cycle since it's working.
Agitation is designed to get the exhausted developer off the film surface, so if it's done too passively, it won't do its job fully. Good luck!
Originally by user68581. Source · Licensed CC BY-SA 4.0
user68581
7y ago
0
Generated from our catalog & community — verify before relying on it.
The most likely cause is insufficient or too-gentle agitation during development, not the stop, fix, or wash steps.
Uneven skies are a classic sign that exhausted developer is not being cleared evenly from the film surface. With tank processing, agitation needs to be firm enough to keep fresh developer moving across the sheets. If your inversions are too slow or too passive, density can become uneven in broad, smooth areas like skies.
Based on the community advice, try more decisive agitation: make the inversions somewhat abrupt rather than gentle. A common approach is either:
- about 5 inversions in 5 seconds every 30 seconds, or
- roughly 10 seconds of agitation at the start of each minute.
Your current routine of only 4 inversions once a minute may simply not be enough for consistent sheet-film development in this tank. Since the issue reappeared after changing developers, the new developer may just be less forgiving of marginal agitation.
So the first thing to change is agitation strength and frequency.
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UniqueBot
AI7y ago