Is this under-agitation?

ediz7531 · Oct 25, 2022

I don’t know if this is the right sub-forum, but seemed the closest to topic.

I’ve recently started trying Ilford’s agitation method: 4 inversions in 10 seconds every minute.

The sky in this image seems quite uneven to me.

Wondering people’s thoughts as to whether this is the result of under agitation.

10/2022 by EI, on Flickr

MattKing · Oct 25, 2022

I've moved this to the B&W: Film, Paper and Chemistry sub-forum, because that is where most of the discussions about uneven development end up.
Can you give us more details please about film type and format, developer, tank and reels?
This is, of course, the result of a scan/digitization of a negative.
Can you see the unevenness on the negative itself?
May we see a backlit digital image of the negative itself, including the edges and spaces between the frames?
It is not unusual for unevenness to be a consequence of the scanning/digitization process, rather than the negative itself.

otto.f · Oct 25, 2022

ediz7531 said:
4 inversions in 10 seconds every minute.

Is normal.
which film is this. Ilford reported some problems with 120 FP4+

pentaxuser · Oct 25, 2022

No it has nothing to do with Ilford's agitation regime. This has worked for me and thousands or maybe tens of thousands of others

The answer lies elsewhere

pentaxuser

Vaughn · Oct 25, 2022

On SS reels, I have found 120 film needs more agitation during fixing than I expected -- more than development -- to clear the film properly. YMMD

ediz7531 · Oct 25, 2022

Thanks Matt for moving to the appropriate sub-forum. I apologize for having missed the right place.

More information:
This was using 120 Delta 400 rated at 400. Developed in Pyro 510 at 1:100 for 11 minutes. Using stainless steel tank (the Samigon ones that fit 1 medium format roll) and Hewes reels. I have seen this when developing in D-76 at 1:1 as well before. I scanned with a coolscan 9000.

I inspected the negative, and I do see the unevenness on the negative itself. I tried to take a photo but it’s very hard to capture it. Nonetheless here it is.

Untitled by EI, on Flickr

ediz7531 · Oct 25, 2022

Vaughn said:
On SS reels, I have found 120 film needs more agitation during fixing than I expected -- more than development -- to clear the film properly. YMMD

I've only heard of over/under agitation during development, not fixing, causing un-even negatives. Can you kindly elaborate?

MattKing · Oct 25, 2022

ediz7531 said:
I've only heard of over/under agitation during development, not fixing, causing un-even negatives. Can you kindly elaborate?

Sometimes incomplete fixing can lead to the negatives not fully clearing. Insufficient agitation can result in localized incomplete clearing. The good thing is that you can repair this by fully re-fixing the film.

aparat · Oct 25, 2022

Could you please confirm that these striations run lengthwise?

ediz7531 · Oct 25, 2022

aparat said:
Could you please confirm that these striations run lengthwise?

Yes, they run lengthwise (up/down of the image) indeed.

ediz7531 · Oct 25, 2022

MattKing said:
Sometimes incomplete fixing can lead to the negatives not fully clearing. Insufficient agitation can result in localized incomplete clearing. The good thing is that you can repair this by fully re-fixing the film.

Thank you. I think I've used this batch of fixer (TF-4) for about ~ 10 developments, so I wouldn't have guessed that it's too spent. I fixed for 5 minutes, for 30 seconds every minute. I could probably try to re-fix for another 5 minutes and report back.

jimjm · Oct 25, 2022

If the streaking is still visible after re-fixing, consider your agitation technique during development.
The timing scheme seems fine, but how are you agitating the tank? A common method many use is to give the tank a half-twist as you invert it, then tap the tank on the counter before setting it back down after the last inversion. The goal is to introduce random developer flow over the film, which helps to reduce streaking of the type that you've shown.

Vaughn · Oct 25, 2022

ediz7531 said:
I've only heard of over/under agitation during development, not fixing, causing un-even negatives. Can you kindly elaborate?

In my case, I was seeing incomplete silver removal along the edges of the film (where the film is next to the reel spirals) -- causing a need for extra burning-in along the sides of the print. I went to almost constant agitation during fixing (120 in single and double SS reels and tanks) and I got complete fixing.

I use the toss-it-over-your-shoulder technique -- good exercise with the big tanks!.

ediz7531 · Oct 25, 2022

jimjm said:
If the streaking is still visible after re-fixing, consider your agitation technique during development.
The timing scheme seems fine, but how are you agitating the tank? A common method many use is to give the tank a half-twist as you invert it, then tap the tank on the counter before setting it back down after the last inversion. The goal is to introduce random developer flow over the film, which helps to reduce streaking of the type that you've shown.

This is a good point. I'm using the straight down and up inversion, no twisting. I would have guessed there is enough turbulence from this motion alone, although my fluid dynamics is a little rusty
Worth trying a small twist for sure.

So I'll try refixing first and then alter agitation method after if it's still there.

pentaxuser · Oct 25, 2022

ediz7531 said:
This is a good point. I'm using the straight down and up inversion, no twisting. I would have guessed there is enough turbulence from this motion alone,

I hope the refixing and the twist in agitation works for you but I have to say that straight up and down inversion has always worked fine for me

I'd have thought that if further refinements were required then Ilford or Kodak might have at least hinted at this

pentaxuser

Sirius Glass · Oct 25, 2022

I would rap the tank on a rubber block after I filled the tank. Do 3 or 4 inversions to start and then 2 or 3 inversions every 30 seconds.

ediz7531 · Oct 25, 2022

So re-fixing didn't make the issue go away, which leads to (under) agitation problems during developing as the likely culprit?

If this is under-agitation during developing, one thing i'm puzzled by is that for 35mm you get Bromide drag as a result of under-agitation. In that case, my recollection is that the dark lines (on the positve image) trace back to the sprocket holes, and follow gravity.
Now, wouldn't I get lines that follow gravity here too? The artifact lines here go vertically along the image I posted, but the way 120 roll gets loaded on a stainless steel tank, the gravity vector would go from side to side in the image here.

MattKing · Oct 25, 2022

It could also be due to agitation that is insufficiently random.
Whenever I invert a tank to agitate, I also impart some rotation.
The best way to accomplish this, I find, is to invert a tank by putting one hand on top and one hand on the bottom, and then inverting the tank by rolling my hands so that the top hand ends up on the bottom, and the bottom hand ends up on top. This automatically adds a rotation component.
I can obtain the same effect with a single hand, but it helps to visualize it by first using two.
I also like to hear the liquid tumble through the reel and film.

Don_ih · Oct 26, 2022

Developer is too dilute, so it exhausts too rapidly when not being agitated. Yet the liquid does still move slowly, so some areas get a bit more development.

Alex Benjamin · Oct 26, 2022

ediz7531 said:
I’ve recently started trying Ilford’s agitation method: 4 inversions in 10 seconds every minute.

This is Ilford's recommended agitation method for its own developers. Nowhere do they state it should be used universally, nor do they mention pyro developers, which are different beasts all together.

With 510 Pyro and Pyrocat-HD, recommendation is always constant agitation for the first minute. After that you either follow with 5-10 seconds agitation every 30 seconds or every minute (see, for example, Sandy King on Pyrocat-HD development procedure) in case of normal agitation, or you have different options in case of minimal agitation (often used with 510 Pyro). In the latter case, a pre-soak is recommended.

PMK, which I've never used, also has its own agitation scheme. Some documentation mention continuous 1st 15 seconds and 2 inversion every 15 seconds thereafter.

With pyro, you also have to make sure you use a water stop bath. I do three water changes with 30 seconds continuous agitation each. If you had an agitation problem resulting in unevenness, it might have been here.

That said, if you say that you've had the same problem with D-76, then I'd look elsewhere.

Alex Benjamin · Oct 26, 2022

Alex Benjamin said:
This is Ilford's recommended agitation method for its own developers. Nowhere do they state it should be used universally, nor do they mention pyro developers, which are different beasts all together.

With 510 Pyro and Pyrocat-HD, recommendation is always constant agitation for the first minute. After that you either follow with 5-10 seconds agitation every 30 seconds or every minute (see, for example, Sandy King on Pyrocat-HD development procedure) in case of normal agitation, or you have different options in case of minimal agitation (often used with 510 Pyro). In the latter case, a pre-soak is recommended.

PMK, which I've never used, also has its own agitation scheme. Some documentation mention continuous 1st 15 seconds and 2 inversion every 15 seconds thereafter.

With pyro, you also have to make sure you use a water stop bath. I do three water changes with 30 seconds continuous agitation each. If you had an agitation problem resulting in unevenness, it might have been here.

That said, if you say that you've had the same problem with D-76, then I'd look elsewhere.

As an addendum to this I'll add that one of the reason pyro developers are more subjected to the effects of agitation is their sensitivity to areal oxidation (described in The Film Developer's Cookbook), with Pyrogallol-based developers (such as 510 pyro) being even more so than Pyrocatechin-based developers (such as Pyrocat-HD).

Streaking and uneven development is one of the effects of the film's exposition to air, which happens briefly during agitation (inversions). This is why these developers aren't recommended for Jobo types procedures, and why agitation shouldn't be too slow in tanks. Also probably why the more sensitive Pyrogallol-based 510 Pyro works better with limited agitation—the less exposure to air, the better—, while Pyrocatechin-based Pyrocat-HD is better suited for both normal agitation and minimal.

This is my understanding of it from the available literature; it could certainly be better explained by people who have a better grasp at chemistry than I.

gone · Oct 26, 2022

The twisty part is a requirement. If you're just agitating w/o that, those streaks don't surprise me. Don't be shy w/ the counter tap either, give it a good whack on something w/ a folded towel over it to cushion it a bit.

I've been preoccupied whilst doing the inversions over the course of many minutes, and whacked the tank so hard I was sure it would break. Also dropped it a few times on a ceramic tile floor. They're built better than you would think.

NB23 · Oct 26, 2022

Looks like pre-wetted the film? Looks like it.

ediz7531 · Oct 26, 2022

MattKing said:
It could also be due to agitation that is insufficiently random.
Whenever I invert a tank to agitate, I also impart some rotation.
The best way to accomplish this, I find, is to invert a tank by putting one hand on top and one hand on the bottom, and then inverting the tank by rolling my hands so that the top hand ends up on the bottom, and the bottom hand ends up on top. This automatically adds a rotation component.
I can obtain the same effect with a single hand, but it helps to visualize it by first using two.
I also like to hear the liquid tumble through the reel and film.

NB23 said:
Looks like pre-wetted the film? Looks like it.

I don’t pre-soak.

NB23 · Oct 26, 2022

ediz7531 said:
I don’t pre-soak.

Ok good.

A thing to know is that the first minute is the most important. Any error during the first minute will get carried all over the whole process.

Is this under-agitation?

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