Banding on MF B/W negative

Just developed a 120 film. One frame with a large empty sky area shows banding that I can't explain.
Neopan 400 stored in fridge. Home-mixed D-76. 1+1, 12'30"@20°C.
Exposed in a Rolleicord, so up-down is the lengthwise direction of the film; horizontal in the dev tank (Paterson).
D*****l image shown below has been obtained with a V700 and contrast-enhanced to make the problem stand out.
Not a s*****r calibration issue : I repeated after swapping the strip from one to the other slot of the Betterscanning holder; defect unchanged. Turned the 3-frame strip head-tail: unchanged.

A long shot at a possible explanation. My agitation routine: every minute, two inversions, followed by a twirling motion that should set the developer rotating; how fast? for how long? could that induce bromide drag along the long dimension of the film, imprinting an image of dev exhaustion onto the uniform sky area?

Anybody with similar experience? Is that a "known issue" with pure rotary agitation, e.g. with the slotted stick?

I don’t think Paterson are specific about this, but I always twist the twizzle stick backwards and forwards, rather than as you describe; and only straight after filling the tank - thereafter I use inversions only. That’s partly because I can never remember which way up I put the spiral into the tank (i.e. does the film spiral clockwise or anti-clockwise?), partly because I see its function as ensuring the chemical reaches all parts of the film asap.

I wonder if your idea of setting up a swirl might produce those streaks if the film spiral is oriented in the opposite direction?

Incidentally, this is the first example of streaks that I’ve seen posted here that doesn’t involve highly dilute developer.

Agitation instructions on this website support what I suggested above.

First inspect the negative itself to see if the problem is really in there. Don't discount a possible scanning problem just yet.

Btw, the odds that this particular problem is agitation-related are really small IMO. Such a thin, even band of minus density is virtually impossible to create using just agitation technique.

I've had a lot of this using Xtol and rotary development. Went away with a 5m pre-rinse, inversion agitation 1m + 10s every minute after that.

Good luck!

FotoD said:

I've had a lot of this using Xtol and rotary development.

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Sorry, I missed a large part of the problem; I wasn't looking closely enough. I agree that the banding across the entire sky is likely associated with agitation.

This has the look of bromide drag. I suggest altering your agitation as follows.

Orbit the tank anticlockwise in an approximately 200 mm-300 mm diameter circle for 2 quick orbits, stop abruptly, and do 2 more orbits in clockwise direction, and so forth. All that's really needed is to strip the thin layer of depleted developer from the emulsion and remix all the developer into a uniform solution of full strength without a concentration of bromide (bromide is released by development) in contact with the emulsion.

This gives me perfect results with any roll-film tank, those that leak when inverted and those that don’t. The agitation is adequate for even development and generates no developer-displacing foam. I’ve used this agitation since 1987 with good results after spoiling films with conventional inversion agitation.

My agitation with hand tanks is: Agitate continuously for the first 30 seconds. Rap the bottom of the tank on the countertop or tabletop to dislodge any air bubbles. Let the film rest for the 2nd 30-second interval. Then, in the next and every succeeding 30-second interval, agitate for the first 5-6 seconds, rap the tank and let it rest. I never invert, as that introduces air bubbles and aerates the developer, which of course is undesirable.

“Rotation rods” are worse than useless in my opinion. They provide no meaningful agitation and can induce density banding on the film along the top and bottom of the reel.

Ian C said:

This has the look of bromide drag.

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But it's perpendicular to what you'd expect with bromide drag.

Ian C said:

“Rotation rods” are worse than useless in my opinion.

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Experiences vary. The Paterson twizzle stick works 100% reliably for me. But let's not try to 'prove' things to one another. There's certainly no necessity to stick agitation as other methods evidently work just as well or even better (depending on who you ask).

With respect to post #8, whatever works to give the desired results is a good choice. There can be various ways to get good results in film developing. In my case, the agitation recipe I outlined cured the density banding problems I had that appeared identical to that shown in post #1. It also seems to have eliminated the occasional problem with air bubbles adhering to the film and leaving their circular pattern of small, low-density circles.

By inspecting the images of many films that were banded and reading the descriptions of how they were agitated during development, it seems that the banding from bromide drag and the banding from localized turbulence due too-aggressive agitation can look similar. The film shown in post #1 appears to suffer from one of these causes. When I look at the image, I try to figure out how it happened. Diagnosing the actual cause is tricky.

The following excerpt from a Kodak publication mentions both problems:


Eastman Kodak 1985, No. J-1, CAT NO 152 8462, LOC 82-71447, ISBN 0-87985-312-3

Page 12: Agitation of the Developer

“Agitation is probably the least understood and the most abused of all the developing controls, even though it is a crucial process that should be used for consistent and uniform results. When agitation is lacking, a stagnant layer of developer and development by-products forms at the interface of the emulsion and the solution. This stagnant layer is partly depleted in the developing agent and is rich in bromide from the developing emulsion. Since bromide is a restrainer that inhibits developing action, the rate of development is retarded unless fresh developer is supplied to the emulsion. On the other hand, if the developing solution is properly agitated, fresh solution is continually brought into contact with the emulsion, and the normal development rate prevails.

Lack of agitation also contributes to another processing problem. Without agitation, the stagnant layer, which is heavier than the fresh developing solution, begins to sink slowly to the bottom of the processing vessel. As it sinks, it tends to leave streaks on the processed negative. Good agitation overcomes this tendency toward uneven development.

Line and point images are subject to several adjacency effects, that can, in part, be traced to insufficient agitation. Such effects often show up as excessively dark edges, or as low-density halos outside dense images. The effects are usually minimized by vigorous agitation throughout development.

In general, proper agitation is most important for the initial stages of development. That is the time that the gelatin is swelling and development is just beginning. Unevenness in the distribution of fresh developer at this time usually causes rather severe effects.

Agitation techniques vary, and the particular method used will depend on the manner of development. Agitation should always consist of movements that will not cause a current of solution to flow constantly in any one direction. Such currents are the cause of increased density.”

If you want to continue using the twist agitation as part of your routine, do it in the other order - twist first, invert immediately afterwards.
My preference is to include some twist in every inversion movement.
Here is what I tell people who ask me about agitation:
"When you agitate, you want to combine both inverting and rotating, and you should be hearing the fluid tumble through the film.
To get an idea of how the tank should move, pick up a can or bottle similar in size to a developing tank. Hold one end in one hand, and the other in your other hand. Start with the tank vertical - one hand will be above the other. Then rotate your forearms and wrists so that the hands switch positions with each other. The "tank" will naturally both turn over and rotate. Now rotate your forearms and wrists back to the initial position. You have just completed an agitation cycle."
I hope this is useful.

Thank you all for reading and taking the time to provide feedback !

Info #1. I do not use the twizzle stick. I was just mentioning this as a possibility of the same symptom arising from similar cause (rotating liquid). Maybe I should have used the word "orbit" rather than "twirl" in the description of my agitation.

Info #2. The problem frame was #11/12. So it was on the inner part of the spiral, with the emulsion facing just developer (no next-turn film), and in that inner part, the rotation imparted by the orbiting motion can (I guess) persist longer than for liquid trapped between neighbor film turns, possibly dragging development products in a laminar flow.

As concerns the cause of the problem, the jury is still out as far as I'm concerned. Following the two posts by koraks #4+#6, I inspected the negative with a loupe, and could not see the banding. Which does not prove that it does not exist at a level too low for eye detection (the image shown has enhanced contrast).
Next steps are:
1. Produce a high-contrast positive by pure analogue process, using X-ray film.
2. Dust off my Epson 1650 to produce an alternate digital image
Due to existing commitments, this may take a couple of days; I assume that those who were kind enough to respond will be automatically notified when I post the outcome.

As concerns agitation techniques, it seems that I commited two sins. One, basic, was to improvise (orbiting) over what was previously working (inversion). Once more: be consistent! The other one was to create a rotation of the liquid always in the same direction. I take note that good results can be obtained by proper rotation or by inversion. The method proposed by Ian Grant is an interesting twist (pun intended) that I might try out.

Back when I used a lot of 120 film, I had to spend an entire afternoon finding an agitation method that wouldn't give me banding and unevenness. I unrolled a roll of film, flipped on the room lights for a fraction of a second, loaded the film on the reel, developed, pulled out the film and held it up to the light. I went through five or six rolls like that before I found an agitation scheme that gave fairly even results. I found that I was initially agitating much too gently. I ended up agitating every 30 seconds with four to five rather rapid inversions and twists.

Tray processing sheet film ended up being a lot less finicky.

Best,

Doremus

I have been using a rotary processor for a short while now and no longer see banding/uneven skies. Robert Adams' approach to even skies is (was?) to tray develop his 120 film, taping the ends to a bit of backing paper between to hold on to, to form a loop that he constantly moved/dipped in a tray of developer. Has to be done in complete darkness, of course.

Pieter12 said:

I have been using a rotary processor for a short while now and no longer see banding/uneven skies. Robert Adams' approach to even skies is (was?) to tray develop his 120 film, taping the ends to a bit of backing paper between to hold on to, to form a loop that he constantly moved/dipped in a tray of developer. Has to be done in complete darkness, of course.

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Also known as the “Adams Shuffle”.

As announced yesterday, I made further tests. I did make the contact positive on Xray film and dusted off the Epson 1640U. But neither was actually needed.

The answer --to the question "is it on film or a s*****r artifact?"-- came from a simple experiment. Still with the V700, but in 8x10 mode. I have the freedom to place the negative anywhere on the glass, with a small piece of anti-glare glass to keep it flat, and being careful to leave the calibration area completely unobstructed. After a few experiments, I rotated the film strip 90°. Result below (contrast enhanced), shown sideways (as-scanned) on purpose for clarity.



The stripes in the sky are still here, still aligned with the length of the film strip. They are real, i.e. present on the film.
Disregard the "stripes" on the surface of the lake; they are real, being a reflection of the distant snow patches.
There is also the dark stripe on the right side of the picture (on the bottom as shown above); a separate issue IMO. That edge of the picture frame (on the top of the Paterson spiral) is in contact with the spiral; examination shows that the border on the other side is slightly wider, so that the image does not contact the spiral; the width of the image zone being correct at 56mm. Another camera will have a different centering of the image window... And, anyway, my enlarger holder crops slightly.

Which takes us back to agitation techniques. Gratefully acknowledging the several pieces of advice given by responders, describing methods that presumably work, and rather than switch to a new-to-me method, I will revert to pure inversion, and increase from my current two inversions up to five. Based on:
- swallowing my pride and consulting: https://www.ilfordphoto.com/beginners-guide-processing-film/
- the post of Doremus Scudder who systematically went after uneven skies
- other posters mentioning their positive outcome with inversion
Again, rotation may well work, but I have to choose one method.

For the benefit of anyone reading this thread in the future, an extra bit of information. At some point I had small fuzzy dark spots near the top edge of the film (bubbles??); not seen previously (change of water quality?). This was cured by increasing the volume of developer from the 500cm3 recommended by Paterson to 525cm3.

To finish on a positive note, a (technically at least) better frame from the same film. And thanks to all those who provided input.

bernard_L said:

I have to choose one method.

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If it doesn’t seem too impertinent, why? Why not follow the instructions that come with the tank you have?

snusmumriken said:

If it doesn’t seem too impertinent, why? Why not follow the instructions that come with the tank you have?

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Agitation of the processing solutions can be by inversion of the tank using the flexible water tight cap provided, or by rotary agitation using the agitation rod also provided.

good advice from a company that has been around for ~60 years

and equally good advice from a company that has been around for ~140 years

Fit the sealing cap and turn the tank upside down four times during the first 10 seconds and again for 10 seconds (that is four inversions) at the start of every further minute to agitate the developer. Each time you invert the tank tap it on the bench to dislodge any air bubbles which may have formed on the film.

After posting a problem, and gratefully acknowledging advice, I had to give a conclusion Re: what I do. Anyone else remains free to use his/her preferred method; completely different issue.

bernard_L said:

Agitation of the processing solutions can be by inversion of the tank using the flexible water tight cap provided, or by rotary agitation using the agitation rod also provided.

Click to expand...

From the Paterson tank instructions:

Agitation​

After pouring in the first solution, immediately insert the agitator and twist sharply back and forth three or four times, then lightly tap the bottom of the tank on the bench to dislodge any air bubbles which might form on the surface of the film. Now push the cap on and make sure that it fits all the way round.

At the end of the first minute and of each subsequent minute, invert the tank, at once returning it to the upright position, and tap the tank on the bench as before.

Pieter12 said:

I have been using a rotary processor for a short while now and no longer see banding/uneven skies. Robert Adams' approach to even skies is (was?) to tray develop his 120 film, taping the ends to a bit of backing paper between to hold on to, to form a loop that he constantly moved/dipped in a tray of developer. Has to be done in complete darkness, of course.

Click to expand...

I recall that when I first learned to develop film o/a 1964, I used a ceramic dish that had a fat removable ceramic roller built in; pour the developer into the dish, install the roller, pass the film (I was using 120) under the roller (and hence into the developer) and up out the other side, grab the two ends and rock the film up and down -- in complete darkness, of course. Worked well; I've probably got some old negatives somewhere from those early efforts.

Doremus Scudder said:

I found that I was initially agitating much too gently. I ended up agitating every 30 seconds with four to five rather rapid inversions and twists.

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I’m late to this thread. Twenty years or so ago, when minimal agitation schemes were becoming popular, I interpreted minimal as meaning gently jiggling the film during agitation. I got lots of banding. I learned that agitation problems come from a lack of vigor in agitating. Regardless of how often or how long you agitate, when agitating really slosh the developer around. If in a tank, do rap it to dislodge the bubbles. If using nitrogen burst, really move the developer around with the burst.

MattKing said:

From the Paterson tank instructions:

Agitation​

After pouring in the first solution, immediately insert the agitator and twist sharply back and forth three or four times, then lightly tap the bottom of the tank on the bench to dislodge any air bubbles which might form on the surface of the film. Now push the cap on and make sure that it fits all the way round.

At the end of the first minute and of each subsequent minute, invert the tank, at once returning it to the upright position, and tap the tank on the bench as before.

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Thank you. Because this document (https://35mm-compact.com/manuels/paterson-uk.htm) is typeset in the same style (headlines bold blue caps, etc...) as the rest of the 35mm-compact website, I had not registered it as being official Paterson instructions, and thought it was one of these enthusiast recipes.
That said, I won't adhere to the single inversion implied by the wording of that document. I take the advice of Doremus Scudder and juan.
I remain weary of rotation because (end of post #9 by Ian C)

Agitation should always consist of movements that will not cause a current of solution to flow constantly in any one direction. Such currents are the cause of increased density.

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(...) and if I would use the initial rotation (purpose?) as in the Paterson instructions, I would heed to your advice (your post #10)

do it in the other order - twist first, invert immediately afterwards.

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now that I've seen the consequence of rotation freewheeling (as it were) and slowly (?) dying off until the next minute.

Do I need to repeat once more that anyone, photrio or elsewhere, is free to agitate as they please?

bernard_L said:

Thank you. Because this document (https://35mm-compact.com/manuels/paterson-uk.htm) is typeset in the same style (headlines bold blue caps, etc...) as the rest of the 35mm-compact website, I had not registered it as being official Paterson instructions, and thought it was one of these enthusiast recipes.
That said, I won't adhere to the single inversion implied by the wording of that document. I take the advice of Doremus Scudder and juan.
I remain weary of rotation because (end of post #9 by Ian C)

(...) and if I would use the initial rotation (purpose?) as in the Paterson instructions, I would heed to your advice (your post #10)

now that I've seen the consequence of rotation freewheeling (as it were) and slowly (?) dying off until the next minute.

Do I need to repeat once more that anyone, photrio or elsewhere, is free to agitate as they please?

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Of course you can agitate any way you like, but you brought along a problem and we are trying to help identify the cause! The Paterson instructions I grew up with (for the System 4, not the Super System 4, though it makes no odds) and which established my agitation style for life () can be found here. IMVHO, the critical phrase wrt your problem is ‘backwards and forwards’.

Anyway, I hope you resolve the issue one way or another.

bernard_L said:

For the benefit of anyone reading this thread in the future, an extra bit of information. At some point I had small fuzzy dark spots near the top edge of the film (bubbles??); not seen previously (change of water quality?). This was cured by increasing the volume of developer from the 500cm3 recommended by Paterson to 525cm3.

Click to expand...

I had those bubbles too, only with medium format, and it was cured by increasing the developer volume exactly as you have done. Perhaps Patterson was looking for a round number for developing volume but I think a bit more volume than 500cm3 is helpful.

snusmumriken said:

Of course you can agitate any way you like, but you brought along a problem and we are trying to help identify the cause! The Paterson instructions I grew up with (for the System 4, not the Super System 4, though it makes no odds) and which established my agitation style for life () can be found here. IMVHO, the critical phrase wrt your problem is ‘backwards and forwards’.

Anyway, I hope you resolve the issue one way or another.

Click to expand...

The link that you just gave
has a better, more explicit explanation
After pouring in the developer insert the agitator and twist the reel backwards and
forwards for a few seconds to dislodge any air-bells which might form on the surface of the film.
Lightly tapping the bottom of the tank on the bench will also help to remove air-bells.
that explains right away the why of the twist. While
has a slightly different wording that left me wondering about the purpose of the twist.
And, I have since forever, tapped the tank after filling, and not lightly.

So, apart from using the second of the two methods to fight air-bells I did, after all, RTFM (except I since long lost the piece of paper). And, with 120, I had air-bells anyway so I had to depart from the mandated procedure, increasing the developer volume above the official 500cm3; see post by @warden above.

bernard_L said:

The link that you just gave

https://photomemorabilia.co.uk/Paterson/Developing_Tanks/Instructions/System4.pdf

has a better, more explicit explanation
After pouring in the developer insert the agitator and twist the reel backwards and
forwards for a few seconds to dislodge any air-bells which might form on the surface of the film.
Lightly tapping the bottom of the tank on the bench will also help to remove air-bells.
that explains right away the why of the twist. While

Paterson film developing tank instructions manual

Paterson Super System 4 film developing tank instructions manual

35mm-compact.com

has a slightly different wording that left me wondering about the purpose of the twist.
And, I have since forever, tapped the tank after filling, and not lightly.

So, apart from using the second of the two methods to fight air-bells I did, after all, RTFM (except I since long lost the piece of paper). And, with 120, I had air-bells anyway so I had to depart from the mandated procedure, increasing the developer volume above the official 500cm3; see post by @warden above.

Click to expand...

My point was that the OP was doing some kind of rotary agitation, but not backwards and forwards. I think it’s likely that unidirectional spin caused his problem - nothing to do with air bubbles.

As for air bubble precautions, one can certainly miss out the twiddle stick, but I find it quicker to use it in those critical first few moments than to get the lid on securely and invert the tank. Each to their own.

I haven’t tried any daylight processes on film for a long, long time, but I do remember using a spiral in a glass beaker (so as to monitor the process) and being impressed by the air bubbles, which had previously been theoretical only.