Banding on negs

[Leitzmac]

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Hi All, particularly those with extensive knowledge of processing neg,

 

I have some negs that have banding leading from sprocket hole to sprocket hole across each frame - essentially thin/dense/thin/dense. I'm presuming this is the result of over aggressive agitation resulting in the developer rushing through the sprocket holes and hence uneven development?

 

Are there any other potential causes?

 

Is this something that happens once in a blue moon and is just bad luck or is it something that should never happen?

 

Thanks in advance,

[kodaktrix]

To my experience this comes from too little agitation. I use Jobo 2500 drums, single and dual. It happend only with the 2-film drum, when I used Diafine which has to be agitated very little. Now I agitate constant the first minute and then once every 30 seconds.

The old Agfa brochure "Faults in negative process" mentions this problem also, and says that even with no agitation there is still a stream of fresh developer through the sprocket holes which develops the neighboring areas more and which you see as strips on the negative.

 

Regards

 

Oliver

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[Don'tknowmuch]

Aha!! Not many moons ago I went through just this, and much of the difficutly of the whole business was trying to describe in words what one was seeing on the negs.

If it's what I had it was quite a simple solution (pun intended) and was fixable (pun also intended).

In my case, (and it sounds exactly the same), it was due to my fixer running out of potency, and I was removing the film before the front of fixer activity had made it across the film (the activity occuring bothon the flat outer survace of the emulsion and on the thin edge of the fixed emulsion). A splash of new fixer and all was sorted, including re-fixing an earlier film that had me foxed.

Hope this helps,

Jim.

[stunsworth]

It's almost certainly an agitation of fixer problem. My agitation technique is to invert the tank 4 times in a 10 second period with smooth inversions. I've always inverted and never bothered with the little stick to rotate the reels inside the tank.

[earleygallery]

There was a thread about this same problem recently. The cause in that case turned out to be too weak/old mixture of fixer, but the same problem is also caused by insufficent agitation.

 

First off, try re-fixing the negs, it might clear it (if it was due to the fixer in the first place).

[rob_x2004]

Couple of questions, and I dont doubt the explanations above.

How come underfixing leaves (Ive never seen first hand only the posted forum examples) tiger stripes across the negs rather than a fixer front radiating out from the sprocket holes?

Is refixing later just hiding or obliterating the evidence of the problem that you created in the first place, similar to dropping undeveloped film into fixer it will clear, taking away any evidence of the exposed negative image?

[osscat]

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Fix removes the undeveloped emulsion leaving these areas either transparent (deep shadow) or leaving patches of developed silver on the neg (shadow detail or other detail) The result is a dense area which translates to a light area on a print.

 

If the fix is too weak and not washed over the film properly then it is likely that the phenomenon described will occur.

 

Similarly, if over vigorous development occurs then dev can jet through the sprocket holes leaving banding where some areas adjacent to the sprocket holes have been developed more than the immediate areas either side of the sprocket hole.

 

Osscat

[Michael Hiles]

I've always inverted and never bothered with the little stick to rotate the reels inside the tank.

 

This is an important point. Rotating developing reels produce eddies around around sprockets with subsequent over development around the sprockets. Agitation should always be by gentle inversion - upside down (2 sec), back (2 sec), do it again twice, and do this whole fandango every 60 seconds. Or follow developer's recommendations for timing. The goal is vigorous and random agitation WHILE AGITATING, but appropriate periods of rest (at least 30 seconds) while the development occurs.

 

Also, there needs to be generous room in the tank for the solution to move. Do not fill the tank. I use an old JOBO tank for 5 films, and I would not load more than 4 (usually 2) and fill with only enough solution to generously cover the film - definitely not a full tank.

 

All this technique came from a pamphlet from Leitz in the 1960s (approx) that dealt with film processing technique. Very useful, and it assures no problems such as dealt with in this thread.

[Leitzmac]

Thank you to all who have posted replies, you have been more than helpful. I think the first thing is to re-fix and if that doesn't work then it would appear the stripes are a result of incorrect agitation.

 

Interestingly I joined the lads for a Forum Meeting in London today which was followed by a visit to the Capa exhibition at the Barbican and James drew my attention to one of the prints which to my surprise showed the dreaded banding! I guess if you are one of the world's finest people still want to display your prints despite clear technical shortcomings.

 

Incidentally anyone who hasn't seen the exhibition I highly recommend a visit - the pictures of the D-Day landings are extremely powerful and the story behind them is one of the greats.

 

Thanks again to all who replied.

[earleygallery]

Interestingly I joined the lads for a Forum Meeting in London today which was followed by a visit to the Capa exhibition at the Barbican and James drew my attention to one of the prints which to my surprise showed the dreaded banding! I guess if you are one of the world's finest people still want to display your prints despite clear technical shortcomings.

 

Capa had his share of processing problems didn't he! Let us know if you manage to rescue your negs.

[Leitzmac]

Capa had his share of processing problems didn't he! Let us know if you manage to rescue your negs.

 

Indeed he did, the problems associated with the D-Day pictures are a prime example - however in retrospect I'm sure he'd be thanking that technician!

[Don'tknowmuch]

Interested to hear if any of our suggestions worked. If, for example, it proved to have been due to poor fixer management it would make me feel a lot better.

Jim.

[Leitzmac]

Interested to hear if any of our suggestions worked. If' date=' for example, it proved to have been due to poor fixer management it would make me feel a lot better.

Jim.[/quote']

 

Hi Jim,

 

Agitation, or lack of, was the problem unfortunately. Sadly there's no quick fix (pun intended) this time - in fact there's no remedy for this problem at all I don't think.

 

Thanks to all for your suggestions.

[rob_x2004]

I still dont understand why underagitation leaves tiger stripes across the negative, rather than a random pattern, or a blooming out from the sprocket holes like the over agitation surge marks.

I know it isnt important and I should just accept that the apple falls down, but it really bugs me.

[earleygallery]

Rob, I am not a physicist but can only imagine that the act of inverting the tank, and the flow of chemicals through the sprocket holes against the flow of chemical passing the top of the reel causes an uneven flow/distribution over parts of the film - maybe a bit like a riptide!

 

Another thing I do now is make sure that I don't invert the tank from the same position/direction each time - might not be necessary but I think it helps to ensure even development.

[Don'tknowmuch]

Mmm... Are you inferring that it was lack of agitation during fixing or developing? If during the fixing, then you could re-fix obviously. I wouldn't think it likely that you would have failed to agitate as you always agitate during developing...

Jim.

[Leitzmac]

Hello Jim,

 

'Twas almost certainly a problem with developing and the distribution of developer, just unevenly spread across the neg. It's a 15 or even 18 roll capacity (not dip/dunk), although is never filled entirely with film. There are two people who develop films in that apparatus, one who has had problems and the other who hasn't (it's not me who did the processing) and there is currently a discussion taking place regarding agitation technique! I will update if and when further details are revealed.

[rob_x2004]

Why dont you post an image from one of the frames? Everyone is assuming the problem you have is the same as Jim showed a week or two ago.