Air Bells
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First try gently rapping the tank bottom with a small block of wood at the end of each agitation cycle. (Instead of using your sink, to preserve the sink.)
If that doesn't clear up the problem, then try 1-drop of Edwal LFN wetting agent per 8-ounces of developer solution. Depending on your developer it will dramatically break up the air bubbles in the tank. Adjust the drops as required. Continue the gentle rapping even with the LFN to get the straggler bubbles.
I'm sure some here will disagree with LFN in the developer, but many (including me) have used it with good success. It's a non-ionic (non-soapy) alcohol-based formula, I believe.
Ken
If that doesn't clear up the problem, then try 1-drop of Edwal LFN wetting agent per 8-ounces of developer solution. Depending on your developer it will dramatically break up the air bubbles in the tank. Adjust the drops as required. Continue the gentle rapping even with the LFN to get the straggler bubbles.
I'm sure some here will disagree with LFN in the developer, but many (including me) have used it with good success. It's a non-ionic (non-soapy) alcohol-based formula, I believe.
Ken
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Rapping the tank after agitation.
I also 'roll' the tank on its side. Let's see if I can describe this: In the air, hold the tank between your hands. Tip it on its side- let's say the top tips to the left hand. Use the left hand to keep the top on and use the right hand to 'spin the tank back and forth- rotate it on its central axis- I do this very quickly, maybe 90-120 degrees total, back and forth 2-3 times. Then rotate the 'base' position of the tank about 120 degrees, repeat, rotate, repeat. This happens in about 5-6 seconds total.
The idea came from hearing that the rolling Jobo system doesn't have problems with air bells due to its rotation on its side.
Happy to be corrected. I do know that I have had almost no bubbles since starting the sideways rolling action, but there could be other explanations.
I also 'roll' the tank on its side. Let's see if I can describe this: In the air, hold the tank between your hands. Tip it on its side- let's say the top tips to the left hand. Use the left hand to keep the top on and use the right hand to 'spin the tank back and forth- rotate it on its central axis- I do this very quickly, maybe 90-120 degrees total, back and forth 2-3 times. Then rotate the 'base' position of the tank about 120 degrees, repeat, rotate, repeat. This happens in about 5-6 seconds total.
The idea came from hearing that the rolling Jobo system doesn't have problems with air bells due to its rotation on its side.
Happy to be corrected. I do know that I have had almost no bubbles since starting the sideways rolling action, but there could be other explanations.
Air bells are worse with some film/developer/water combinations.
I did some practical testing about 5 years ago and found that like Chip says a pre-soak doesn't help, I also found that rapping the tank was only helped slightly. I tested different tanks Paterson, Jobo & SS.
The key is the hardness of the water supply and whether the developer has a softening agent like Sodium Hexametaphosphate or EDTA, some films contain small traces of surfactants (wetting agents) as they help in the coating process.
These air-bells are in a Paterson tank after a pre-soak, I found the only way of eliminating them was adding a very slight amount of Wetting agent - one or two drops (exact amount may depend on your wetting agent). the amount has to be minimal as excess may lead to foaming during agitation which can also cause problems.
Ian
I did some practical testing about 5 years ago and found that like Chip says a pre-soak doesn't help, I also found that rapping the tank was only helped slightly. I tested different tanks Paterson, Jobo & SS.
The key is the hardness of the water supply and whether the developer has a softening agent like Sodium Hexametaphosphate or EDTA, some films contain small traces of surfactants (wetting agents) as they help in the coating process.
These air-bells are in a Paterson tank after a pre-soak, I found the only way of eliminating them was adding a very slight amount of Wetting agent - one or two drops (exact amount may depend on your wetting agent). the amount has to be minimal as excess may lead to foaming during agitation which can also cause problems.
Ian
Presoak will encourage it is wetting you need bubbles should not matter.
borax or carbonate are excellence wash aids adding surfant waste of surfant but should not be a problem
Pour in minimal developer to Patterson and invert and hold for five seconds restore upright and hold for five seconds
Repeat five or more times.
top up if worried
This works for 8x pattersons multis wear gloves and do it over bath or shower tray...
Hitting a Patterson is like putting a 75mm solid AP into side panel of a Tiger tank might not need 2nd one for kill.
borax or carbonate are excellence wash aids adding surfant waste of surfant but should not be a problem
Pour in minimal developer to Patterson and invert and hold for five seconds restore upright and hold for five seconds
Repeat five or more times.
top up if worried
This works for 8x pattersons multis wear gloves and do it over bath or shower tray...
Hitting a Patterson is like putting a 75mm solid AP into side panel of a Tiger tank might not need 2nd one for kill.
This is tricky issue because surfactants:
1.) are beneficial as they counter the trapping of air at filling or inversion
2.) are harmful they stabilize bubble once evaded to the surface.
But there are different prerequisites for building foam. Thus there is a way to diminish that second character trait by using the apt surfactant.
As indicated above there are no/low foaming surfactants.
1.) are beneficial as they counter the trapping of air at filling or inversion
2.) are harmful they stabilize bubble once evaded to the surface.
But there are different prerequisites for building foam. Thus there is a way to diminish that second character trait by using the apt surfactant.
As indicated above there are no/low foaming surfactants.
Fortunately, this is a problem I've never had. I give my tank a hard rap on the counter top nearly every agitation cycle. You might want to use a wood block of a soft wood such as pine, laid out on the counter top to cushion the hit. I probably rap the tank excessively, but never had any air bells either. Maybe let the water that you use for your developer, assuming you don't just use it straight up, sit for a couple of hours after coming out of the tap. I always use distilled water out of a bottle for developer though.
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How do you know for sure if you have air bells?
I never had a problem with trapped air but I rap my tanks on a table top pretty hard and I always use metal, not plastic, film tanks.
In developing tanks it is air, in beer glasses it is carbondioxide.
Or is there a difference between "bells" and "bubbles" you might refer too?
Never had air bubbles, at least no artefacts caused by them. But as Ian indicated it may be a problem of certain circumstances.
I concur 100%. Also, draw the water you are going to use ahead of time and let it stand to outgas any entrained air.
A presoak may induce...
yes but there is a lotta carbondioxide in air or nitrogen...
http://en.m.wikipedia.org/wiki/Guinness
although you may not call it (stout) a beer?
Smack the tank with the palm of your hand several times.
I use distilled water to mix my developer (normally HC110 1+63 as a one shot). In my stainless tank, I normally agitate with inversions for the first 30 seconds, rapping the tank sharply on a wooden surface after every couple of inversions. (I also rotate the tank about 50 or 60º between each of the inversions. After that I go four or five inversions every minute and have not seen any problems with bubbles.
The other point is that I have measured how much liquid it takes to cover the reel and about a 1/2cm more, leaving air space at the top because filling the tank solid hampers the agitation. It might seem counter-productive to be sure there's air in the tank, but I suspect allowing the agitation action to be more vigorous helps to sweep away the bubbles. (That's my story and I'm sticking to it!
)
The other point is that I have measured how much liquid it takes to cover the reel and about a 1/2cm more, leaving air space at the top because filling the tank solid hampers the agitation. It might seem counter-productive to be sure there's air in the tank, but I suspect allowing the agitation action to be more vigorous helps to sweep away the bubbles. (That's my story and I'm sticking to it!
)I've used Photo-Flo in my dev, distilled water, I had a 4-reel Nikor tank tn the early 70s that I rapped so hard the bottom became a perfect semi-sphere! Ian C. sent me a suggestion to let the film stand in tempered water for 2 min, rap, & then use figure-8 agitation rather than inversion. That's worth a try!
Rather than a wood block I use a 1/4" thick block like this http://www.michaels.com/on/demandware.store/Sites-MichaelsUS-Site/default/Search-Show?q=linoleum to thump the tank on several quick light taps just after a new chemical is added. [i learned this from Per Volquartz. Look him up on APUG and Google.]
Proper agitation is always important
My testing showed that tapping the tank only removes some of the air bells there were still plenty left.
Ian
Does this happen with stainless-steel tanks and reels? I've never had them, and I don't really rap my tanks either. The picture earlier in this thread shows bubbles on a plastic reel. Plastic is usually hydrophobic, whereas stainless steel is more hydrophillic; also, the stainless-steel reels are made of round material which maybe doesn't trap bubbles as much.
When an air bell comes along, you must whip it.
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