Agitation, surge, and uneven development?

runswithsizzers · Oct 21, 2024

I have been noticing pale edges on my darkroom prints from b&w 120 negatives. My assumption is, this may be caused by "surge" -- that is, an increase in development at the edge of the reels due to turbulence when agitating. I am using stainless steel tanks and reels, sometimes one 120 reel in a 16 oz. tank, and sometimes two 120 reels in a 32 oz. tank.

I don't think my agitation technique is overly agressive: initially, 30 seconds of continuous inversions, followed by 2 inversions per each additional minute. I have been trying to make each inversion a smooth, moderately slow movement, taking about 2 seconds for each full rotation.

So I have two questions about what other factors might be causing my uneven development:

1. Should my tank be completely full, with no air?
That is, if there is enough fluid to safely cover the reel(s) but not enough to completely fill the tank, will that air space result in over agitation / surge / uneven development? I checked four basic how-to-develop-film instructions from Kodak, Ilford, Henry Horenstein, and Anchell/Troop. Horenstein does say, "...it's a good idea to to fill your tank fully with solution," but I can't find where the others specifically say if the tank should be completely filled -- or not.

2. Should the reels be allowed to move up and down with each inversion?
For example, if I put two 120 reels in my 32 oz. tank, there is about 1-1/2 inches of space between the top of the reels and the top of the tank. So, the reels can slide up-and-down almost 1-1/2 inches with each inversion. What I don't know is this, was the tank designed that way specifically to allow the reels to move? I could put an empty 35mm reel on top of the 120 reels to prevent the reels from moving, and thereby possibly reducing turbulence when agitating -- but should I? In other words, is it necessary for the reels to move up and down to insure agitation is effective?

pentaxuser · Oct 21, 2024

Well, if your agitation as you describe it, is the cause of such problems as you describe then I should being seeing the same effect and for about the nearly 20 years I have been developing

In the tanks I use which are Jobos and Dursts I have found that filling the tank with the amount of liquid that each maker specifies get me close to the rim anyway so if the film is adequately covered and mine always were by the specified quantities then I see no benefit in adding any extra. My reels fit in the tanks both for 35mm and 120 and under the lids in such a way that there is no room for movement. I always thought that each tank if its for a 35mm or 120 film respectively was designed to prevent movement of the reels such that for some of the time the reels can rise above the surface of the specified level of developer

On balance I think there may be other more likely causes but I have no idea what as it sounds like what you are doing is similar to what I am doing. I cannot see any obvious causes in what you are doing

pentaxuser

runswithsizzers · Oct 21, 2024

@pentaxuser, thanks for your reply. I am using older stainless tanks, some of them not marked by a brand, so I have no way of knowing what volume of the liquid the maker may have recommended.

For my 32 oz tank, with two 120 reels in it (but no film), 900 mL covers the reels plus about 1-inch extra liquid -- but leaves about 1/2-inch of air space. That is the amount of developer I have been using. Today, I will use 32 oz. which should fill the tank completely.

I believe the 16 oz ss tanks are designed to take either two 135 reels or one 120 reel. With two 135 reels, there is very little room for the reels to move. But with one 120 reel in my 16 oz tank, the reel can move up and down about 3/4-inch (19mm). And, as previously mentioned, with two 120 reels in my 32 oz tank, the reels can move up and down about 1.5-inches (38 mm). That may be a consequence of trying to make one tank work for several reel sizes, I don't know. It seems like if it was critical that the reels not move when the tank is inverted, there would be spacers marketed to limit movement when using 120 reels, but I am not aware of any.

MattKing · Oct 21, 2024

Please show us backlit images of the negatives themselves, with the film rebates, the edge printing, and the space between frames visible.
Movement of the reels won't hurt anything (other than your ears!) as long as the reels don't spend too much time out of the solution.
Personally I prefer a bit more air space in thee tank. When the tank is inverted, the air should tumble and twist and gurgle through the reels.

JerseyDoug · Oct 21, 2024

To rule out light leaks in the camera it would be helpful to know if the pale edges on the prints are on one side, two opposite sides or all four sides, and which sides in particular if it's less than four. Also if the film moves through the camera horizontally as with a RF or vertically as with a TLR.

(The pale edge on one side of some of my prints from 120 negatives turned out to be caused by a faulty light seal on one of my Hasselblad backs.)

_T_ · Oct 21, 2024

When I first began developing 135 with stainless steel tanks and reels I noticed two marks of increased density that ran all along each of the long edges of each roll of film. I looked it up on apug and found many people suggesting that surge marks are very unlikely, but that if they are happening they could be caused by too much agitation. I cut manufacturer agitation suggestions in half and like magic the marks on the long edges of my rolls disappeared.

I don't know if this would work for you as well, but it solved my problem and only risked a single roll of film.

koraks · Oct 21, 2024

runswithsizzers said:
I have been trying to make each inversion a smooth, moderately slow movement, taking about 2 seconds for each full rotation.

Doesn't really have to be slow. The purpose of agitation is...to agitate. So it can be brisk - in fact, it really should be.

runswithsizzers said:
1. Should my tank be completely full, with no air?

A little air on top will help to create a turbulent flow pattern.
I'm not of the "full tank" persuasion and instead use enough volume to cover the reels. This has always worked well for me (and others).

runswithsizzers said:
2. Should the reels be allowed to move up and down with each inversion?

It doesn't really matter unless there's a risk of one or more reels settling too high up the center column, leaving it partially exposed above the fluid level.

Perhaps you can post some contact prints or good scans from affected negatives so we can get a feeling for the problem you're running into. At this point I'm not convinced that agitation is the problem, per se. And if it is, I wonder if it's really a case of too much agitation - it doesn't sound like it, at all (the opposite, more likely).

120 roll film is always slightly tricky since the images run so close to the edge, and density variations tend to occur predominantly along the edges of the film as well.
Some find that a pre-soak helps, others swear that a pre-soak gives them these problems. My advice would be: if you're doing a pre-soak, try skipping it. If you're not doing a pre-soak, try one. See if it makes a difference.

Doremus Scudder · Oct 21, 2024

Back when I used a lot of 120 film, I started out with the same problem. I spent an afternoon in the darkroom unrolling roll after roll of film, exposing them quickly to light to yield a middle gray and then spinning it on to the reel and developing them with different agitation and fluid levels to see which combination gave me no increased density on the edges.

Result: leave a bit of an air space; full tanks don't let the developer mix and flow randomly. And, most importantly, agitate much more vigorously than I had been for 135 film. I felt like I was shaking cocktails but that's what seemed to work best.

Hope this helps,

Doremus

runswithsizzers · Oct 21, 2024

I am using a Mamiya C220 TLR which moves the film from bottom to top. The lighter areas of the prints are on the right and left edges of the scene, but not the top and bottom of my prints.

To my eye, the density gradient is less obvious on the negatives than it is on the prints, but here are examples. From the the edges of the fimstrip, the density decreases and gets lighter in the direction of the arrows.

On the prints, the lighter area is more noticeable close to the left and right edges (which would be the top and bottom of the photo of the negative, below).

After reading the replies, so far, I am beginning to think these density gradients may be unrelated to my development methods, because either, a. I am doing everthing the right, or, b. it doesn't really matter.

logan2z · Oct 21, 2024

Doremus Scudder said:
I felt like I was shaking cocktails but that's what seemed to work best.

That's what I've always read not to do But it seems like what works for one person has disastrous results for someone else. That's why it took me so long to get up the nerve to develop my own film at home, it seemed there was so much contradictory information about the process.

_T_ · Oct 21, 2024

runswithsizzers said:
On the prints, the lighter area is more noticeable close to the left and right edges (which would be the top and bottom of the photo of the negative, below).
View attachment 381432

It doesn’t look like you have the problem at all. Look at the density of the street. Perfectly flat and smooth across the frame. There’s no additional density there.

I think I see what you’re talking about in the sky but that’s definitely not due to over agitation. Surge marks from over agitation are much narrower and pronounced.

It looks like you simply captured differences in the color of the sky from one part of the sky to another.

The sky is not one uniform color but darkens as it approaches a 90° angle away from the axis between the viewer and the position of the sun. This effect is especially apparent in wide angle photos of the sky where enough of the expanse is captured to see the distinct variation from one part to another.

runswithsizzers · Oct 21, 2024

_T_ said:
It doesn’t look like you have the problem at all. Look at the density of the street. Perfectly flat and smooth across the frame. There’s no additional density there.

Looking at the Bank negative, can you not see the extra density in the street at the edges? It is slight, especially on the left edge (top as posted), but I can definitely see it. For me, it is easier to see along the right edge (bottom, as posted).

_T_ said:
[...] Surge marks from over agitation are much narrower and pronounced.

I agree. On some prints, I think I was seeing more narrow and more pronounced areas of lightness. That was what got me to thinking it might be surge. Those prints may be in my locker at school, or I may have discarded them. Looking at the negatives, the density gradient is wider and more gradual than what I was expecting to see, compared to what I remember seeing on the prints. I take a closer look at the prints as opportunity presents.

On several prints, the middle third of the scene, no matter what the subject, is printing slightly darker. And the negatives can be seen to be slightly thinner in the same area. So maybe not surge / over agitation -- but something is going on.

koraks · Oct 21, 2024

I'm not seeing it.

I suspect you may be running into a problem with uneven illumination in your enlarger.

MattKing · Oct 21, 2024

koraks said:
I suspect you may be running into a problem with uneven illumination in your enlarger.

+1

Or an issue with the lens.

GregY · Oct 21, 2024

koraks said:
View attachment 381443
I'm not seeing it.

I suspect you may be running into a problem with uneven illumination in your enlarger.

Yes.... That's what i was thinking too

Milpool · Oct 21, 2024

runswithsizzers said:
Looking at the Bank negative, can you not see the extra density in the street at the edges? It is slight, especially on the left edge (top as posted), but I can definitely see it. For me, it is easier to see along the right edge (bottom, as posted).

I agree. On some prints, I think I was seeing more narrow and more pronounced areas of lightness. That was what got me to thinking it might be surge. Those prints may be in my locker at school, or I may have discarded them. Looking at the negatives, the density gradient is wider and more gradual than what I was expecting to see, compared to what I remember seeing on the prints. I take a closer look at the prints as opportunity presents.

On several prints, the middle third of the scene, no matter what the subject, is printing slightly darker. And the negatives can be seen to be slightly thinner in the same area. So maybe not surge / over agitation -- but something is going on.

For what it’s worth I’m pretty sure I’m seeing what you’re seeing - the gradients in the negative seem to be the same gradients as in the positives - except that they are much more pronounced in the positives due to the much higher contrast.

pentaxuser · Oct 21, 2024

logan2z said:
That's what I've always read not to do But it seems like what works for one person has disastrous results for someone else. That's why it took me so long to get up the nerve to develop my own film at home, it seemed there was so much contradictory information about the process.

Yes but fortunately for me I started developing while ignorant of Photrio's existence so I did it according to what Ilford told me and it worked.

Behind every joke there is a lesson of a kind

pentaxuser

Augustus Caesar · Oct 21, 2024

runswithsizzers said:
I have been noticing pale edges on my darkroom prints from b&w 120 negatives. My assumption is, this may be caused by "surge" -- that is, an increase in development at the edge of the reels due to turbulence when agitating. I am using stainless steel tanks and reels, sometimes one 120 reel in a 16 oz. tank, and sometimes two 120 reels in a 32 oz. tank.

I don't think my agitation technique is overly agressive: initially, 30 seconds of continuous inversions, followed by 2 inversions per each additional minute. I have been trying to make each inversion a smooth, moderately slow movement, taking about 2 seconds for each full rotation.

So I have two questions about what other factors might be causing my uneven development:

1. Should my tank be completely full, with no air?
That is, if there is enough fluid to safely cover the reel(s) but not enough to completely fill the tank, will that air space result in over agitation / surge / uneven development? I checked four basic how-to-develop-film instructions from Kodak, Ilford, Henry Horenstein, and Anchell/Troop. Horenstein does say, "...it's a good idea to to fill your tank fully with solution," but I can't find where the others specifically say if the tank should be completely filled -- or not.

2. Should the reels be allowed to move up and down with each inversion?
For example, if I put two 120 reels in my 32 oz. tank, there is about 1-1/2 inches of space between the top of the reels and the top of the tank. So, the reels can slide up-and-down almost 1-1/2 inches with each inversion. What I don't know is this, was the tank designed that way specifically to allow the reels to move? I could put an empty 35mm reel on top of the 120 reels to prevent the reels from moving, and thereby possibly reducing turbulence when agitating -- but should I? In other words, is it necessary for the reels to move up and down to insure agitation is effective?

1. Yes (almost full; leave a small amount of air).
2. No

Alex Benjamin · Oct 22, 2024

koraks said:
I suspect you may be running into a problem with uneven illumination in your enlarger.

Had the same problem as the OP a few months back. Examined the negatives over and over again. Turns out the problem was with the filter carrier on the Beseler enlarger...

rippa_the_hutt · Oct 22, 2024

koraks said:
I suspect you may be running into a problem with uneven illumination in your enlarger.

I do agree with this analysis as I fail to spot a density difference in the foreground tarmac. Is it possible the enlarger is still mounting the 35mm (narrower) condenser (if a condenser enlarger)?

koraks · Oct 22, 2024

Milpool said:
I’m pretty sure I’m seeing what you’re seeing

No, not me. The inversion I posted last night I made on my phone with snapseed. I just made another one with Gimp and had a closer look at it.

I drew in two wiggles.

The yellow one refers to the gradient in the sky, particularly the darker spot in the center. This looks like a perfectly normal gradient to me that was there in real life.
The red wiggle refers to a vertical (in this version), fuzzy dark band along the edge of the frame. A likely cause is a stuck air bubble in the reel that reduced the rate of development along this edge, creating a low density zone. Tap the tank firmly on the counter after pouring in the developer and after each inversion cycle to dislodge such bubbles.

Apart from the sky, there are minute density variations across objects of the same material in the same light, and there's no reason for me to assume these minute density variations are anything but real-world variations in reflectance.

Apart from the single suspected air bubble, these negatives look perfectly fine to me!

250swb · Oct 22, 2024

I'm not seeing enough evidence to decide if it's a problem with the negative or the print so I'll add two instances of the uneven edge in the sky one for the print and one for the negative. For the print could you be getting a reflection off your printing easel? I know the complaint is about pale edges, but if a reflection from the easel lands a little inside of the printed area and not along the outer edge the outer edge will appear to be lighter. And something to check with the camera, unlike many TLR's that generally only have light/dust seals at the catch and hinge ends of the door Mamiya's have foam seals that run the length of the door, so are they in good condition?

Chuck_P · Oct 22, 2024

pentaxuser said:
Yes but fortunately for me I started developing while ignorant of Photrio's existence so I did it according to what Ilford told me and it worked.

Behind every joke there is a lesson of a kind

pentaxuser

This made me laugh......and I don't necessarily disagreee.

runswithsizzers said:
I have been noticing pale edges on my darkroom prints from b&w 120 negatives.

You say pale edges on the print but I see a darker edge as indicated by @koraks in the inverted frame that he posted. Maybe you meant to say darker edges on the print................at the right edge of the bank frame, as noted by @koraks, the vertical darker area of that inverted frame, indicating decreased negative density in that area, is quite apparent in the sky region. Are there other frames from this roll that exhibit the same type of decreased edge density on the negative or just these two frames?..........and btw, the top inverted frame seems normal to me as well, perhaps it's limited to just the bank frame. If it's an isolated frame or two, then that seems to speak toward @koraks observation about a bubble.

runswithsizzers · Oct 22, 2024

Chuck_P said:
[...]

You say pale edges on the print but I see a darker edge as indicated by @koraks in the inverted frame that he posted. Maybe you meant to say darker edges on the print................at the right edge of the bank frame, as noted by @koraks, the vertical darker area of that inverted frame, indicating decreased negative density in that area, is quite apparent in the sky region.

As I said, pale edges on the PRINTs, and darker edges on the NEGATIVEs.

The right edge of the bank negative is somewhat atypical. Yes, on Koraks inverted version, there is a narrow darker area seen in the sky, right at the edge. But that darker is contained within a wider lighter area beginning at the right edge, and fading out about 1/3 of the way into the center of the image. Look down in the lower right corner of Koraks version, and notice the pavement and sidewalk are lighter, compared to the bottom-center. And the left edge of the inverted image is lighter, too, more easily noticed in the sky.

This is the typical pattern I have been seeing in my darkroom prints and inverted copies of the negatives - light on both the left and right edges, and darker in the middle. But apparently, the effect is too subtle to be easily seen on digital screens(?)

Chuck_P said:
Are there other frames from this roll that exhibit the same type of decreased edge density on the negative or just these two frames?..........and btw, the top inverted frame seems normal to me as well, perhaps it's limited to just the bank frame. If it's an isolated frame or two, then that seems to speak toward @koraks observation about a bubble.

I have seen this effect on numerous frames from this roll and from four or five other rolls -- all 120 format.

runswithsizzers · Oct 22, 2024

I am enrolled in a medium format photography class at my local state university. All analog, black and white, only. The photography professor says she has seen 120 negatives like mine before, and she thinks the uneven development of the negatives is due to over agitation.

I will make one last attempt to illustrate the problem. The positive images shown below are inverted versions of digital photos taken of the negatives on a light table. No enlarger or scanner was involved.
Edited to add: The darkroom prints look very much like the positive versions which I have posted here.

Agitation, surge, and uneven development?

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