Twist agitation - has anyone ever done tests?

[MattKing]

How many permutations to randomise agitation are possible with the inversion method?

Just like twist agitation, an infinite number.
But adding the additional non planar directionality means there is even more infinity .
The up and down movement that is unavailable with twist agitation adds a whole new dimension (pun intended).

 

[BrianShaw]

Yes… whole new dimension: I twist agitate, as well as thump the tank to mitigate air bubbles. I shimmy and shake my… to verify the timer accuracy.

 

[Cholentpot]

Never found a difference. Sometimes I'll twizel and rock the tank a bit. I think it's all black magic anyhow.

 

[AgX]

How many permutations to randomise agitation are possible with the inversion method?

I guess that is why Heiland offer that programmable inverting machine.

 

[foc]

I think it's all black magic anyhow

A lot of photographic technique is like that, also.

 

[Cholentpot]

A lot of photographic technique is like that, also.

Developing C-41 at home requires things like taking off one shoe and turning off the closet light in the attic.

 

[MattKing]

Developing C-41 at home requires things like taking off one shoe and turning off the closet light in the attic.

Which for no particularly good reason makes me think of Maxwell Smart.

 

[Sirius Glass]

Developing C-41 at home requires things like taking off one shoe and turning off the closet light in the attic.

No.

1. Load the film on reels and into the tank in the dark.
2. Fill the Jobo processor reservoir with water and bring to temperature along with the chemical.
3. Turn on the Jobo processor.
4. Add and pour off the chemicals in the correct order and for the correct time.
5. Wash the film in the processor.
6. Pour in preservatives, let rotate for 30 seconds, pour out.
7. Remove the tank from processor.
8. Remove and hang film.

There is no need to remove shoes nor turning off the closet light in the attic. In fact the closet light did not even need to be turned on.

 

[Cholentpot]

No.

1. Load the film on reels and into the tank in the dark.
2. Fill the Jobo processor reservoir with water and bring to temperature along with the chemical.
3. Turn on the Jobo processor.
4. Add and pour off the chemicals in the correct order and for the correct time.
5. Wash the film in the processor.
6. Pour in preservatives, let rotate for 30 seconds, pour out.
7. Remove the tank from processor.
8. Remove and hang film.

There is no need to remove shoes nor turning off the closet light in the attic. In fact the closet light did not even need to be turned on.

I don't have a jobo processor. Well, I did score a whole kit but it wasn't operating and I sent it along to a fellow APUGer who can fix it and enjoy it.

Now, with my regular patterson tanks and sous-vide I've tried a bunch of methods. I used to float the tank in the water itself to keep the temp as perfect as possible. For some reason this was worse than pouring the stuff in when tank is on bench. I stopped doing that. Also I switched water sources and then switched back only to switch again.

 

[TunkuFawzy]

I moved from the inversion method (chemicals kept on spilling out and I experienced some bromide drag occasionally) to using the twiddle stick. The results thereafter were ok and consistent. Earlier this week I received a rotary tank processing device which I ordered from some people in Wales. Looks robust enough and will be trying that out later today.

 

[laingsoft]

So many answers in here about "fluid dynamics" The developing and fixing reactions are not anywhere near complicated enough to be significantly affected by any sort of agitation provided you aren't shaking your developer like a martini. Even a gentle swirl with the twizzle stick is going to expose all parts of the film to fresh developer.

I use a twizzle stick when I'm doing c41, I leave the tank in my water bath so the temperature doesn't drop, you can't really do inversions underwater. When I do Rodinal I do inversions sometimes if I'm using a low concentration and the dev times are long. 90% of the time I stick to twizzle sticks because they're cleaner. 30+ y/o tanks tend to drip a bit.

 

[BrianShaw]

shaking your developer like a martini.

Another highly controversial topic: shaken or stirred martinis. Based on a lot of research they should definitely be stirred, and gently to avoid excess aeration and dilution. I recently read on a bartending website that the proper use of a bar spoon for stirring martinis (and manhattans, also, I presume) is with the curve of the spoon facing outward rather than inward. I find that least effective and find that the bar spoon should face inward for a smoother and more effective stir.

 

[laingsoft]

Based on a lot of research they should definitely be stirred

The bars provide the real solution yet again. Twizzle sticks it is.

 

[Cholentpot]

Another highly controversial topic: shaken or stirred martinis. Based on a lot of research they should definitely be stirred, and gently to avoid excess aeration and dilution. I recently read on a bartending website that the proper use of a bar spoon for stirring martinis (and manhattans, also, I presume) is with the curve of the spoon facing outward rather than inward. I find that least effective and find that the bar spoon should face inward for a smoother and more effective stir.

By the time I'm on my second I could care less.

 

[koraks]

The developing and fixing reactions are not anywhere near complicated enough

Has nothing to do with the complexity of the reactions (btw, I challenge you to explain them in depth, let's see how uncomplicated they are), but if the local rate of replacement is sufficient across the entire surface area. Especially with the development step this can certainly be a source of problems. Notorious are the 'wagon tracks' some (including myself) have seen with rotary tanks, or the wave-like artifacts along the edges of sheet film with older Jobo 2509 (non-N) reels, Mod54 holders etc.

The notion that fluid dynamics somehow wouldn't matter is just utter nonsense. If that were true, agitation wouldn't be an issue whatsoever.

 

[Sirius Glass]

So many answers in here about "fluid dynamics" The developing and fixing reactions are not anywhere near complicated enough to be significantly affected by any sort of agitation provided you aren't shaking your developer like a martini. Even a gentle swirl with the twizzle stick is going to expose all parts of the film to fresh developer.

I use a twizzle stick when I'm doing c41, I leave the tank in my water bath so the temperature doesn't drop, you can't really do inversions underwater. When I do Rodinal I do inversions sometimes if I'm using a low concentration and the dev times are long. 90% of the time I stick to twizzle sticks because they're cleaner. 30+ y/o tanks tend to drip a bit.

Another highly controversial topic: shaken or stirred martinis. Based on a lot of research they should definitely be stirred, and gently to avoid excess aeration and dilution. I recently read on a bartending website that the proper use of a bar spoon for stirring martinis (and manhattans, also, I presume) is with the curve of the spoon facing outward rather than inward. I find that least effective and find that the bar spoon should face inward for a smoother and more effective stir.

Correct! Shaking causes oxidation which destroys the aroma and taste of the botanicals.

 

[laingsoft]

Has nothing to do with the complexity of the reactions (btw, I challenge you to explain them in depth, let's see how uncomplicated they are), but if the local rate of replacement is sufficient across the entire surface area. Especially with the development step this can certainly be a source of problems. Notorious are the 'wagon tracks' some (including myself) have seen with rotary tanks, or the wave-like artifacts along the edges of sheet film with older Jobo 2509 (non-N) reels, Mod54 holders etc.

The notion that fluid dynamics somehow wouldn't matter is just utter nonsense. If that were true, agitation wouldn't be an issue whatsoever.

Complexity of what? Black and White is just a restricted and catalyzed oxidation. you aren't really dealing with any sort of interesting intermediates or side products, especially with modern developers. Temperature, Water quality, pH of the developer will all have magnitudes more effect on the final image than agitation. A majority of artifacts can be explained by poor loading technique rather than some sort of hand-wavy "fluid dynamics you need to produce vortices to increase the replenishment rate blah blah" answer.
The argument isn't that fluid dynamics isn't present, it's that it's completely inconsequential in a system as small as a home development tank. Swirl the reels and you're going to get enough fluid movement to do what you need at the concentrations of developers you have, unless you are doing some sort of extremely large batch with an exceptionally low concentration.
Watch some paper develop and you can see what I'm talking about. Slip an exposed paper under the developer careful and try to keep it as still as possible and watch it develop. You will hit a point where the local developer is exhausted and the developer slows down. Do a single tilt of the dish and you'll see development pick back up quickly.

 

[Steve Roberts]

I've used both methods - twiddling in the Johnson tanks and inversion/agitation in the Patterson tanks that I have. IMHO each has one disadvantage. The Johnson twiddling tank has a couple of times left me with the outer end of the film having walked a few inches out of the spiral, leading to worries about it not having been immersed during the whole process. The inversion/agitation tanks that I have usually leak to a greater or lesser extent leaving me a) with chemicals trickling down my arm and b) wondering whether the remaining chemical is sufficient to cover the film. In practice, the results have never given me cause for concern and there are far more significant factors that limit my results than the type of tank I use.
Steve

 

[koraks]

Watch some paper develop and you can see what I'm talking about

I've developed paper and film in trays, in various ways, developed film by hand in tanks, rotary, etc etc. and witnessed the results of different kinds of agitation. And yes, agitation DOES matter. If what you said were true, the kind of defects I mentioned would exist. They do, I still have examples of them around. And no, I'm not going to waste my time trying to convince you. You van do that yourself if you so desire; take some 4x5's, pit them on the outside slots in a 2500 reel and don't mount the black flaps, rotate in your Jobo preferably with something like pyrocat and see first hand what the laminar flow marks on the long sides of the film look like. Same with a Mod54 holder if you don't have a 2500. With 35mm it'd harder to replicate, but if you're (un)lucky you'll see bands of lower density along the length of the film caused by differences in flow between the edges and center axis of the film. Want an easy one? Go ahead and develop a sheet of x-ray film with constant agitation in a tray that just fits the film. By your theory the development should be perfectly even. And yet, you'll see excess density along the edges. Heck, do what you suggested with paper and see if the development "picks right back up" with a single tilt of the tray...LOL!!!

Apparently you've been lucky enough to not have experienced any of the above. Good for you, try to keep it that way. In the meantime I know that the nature of agitation can make the difference between a good image or a reject sheet of film. I contact print a lot and I develop sheet film by hand mostly, because what happens on the edges matters, and with manual agitation in trays I know how to get perfectly even density across the entire sheet. Because agitation is more complex than you seem to realize.

 

[laingsoft]

Yes you can surely make trails in your film if you agitate poorly and choose a high-acutance, staining developer, just like you can crash a corvair if you drive on the wrong side of traffic.

 

[koraks]

agitate poorly

Indeed, and poorly is not just "insufficiently", but mostly "inconsistently across the film surface".

Furthermore, the "corvair on the wrong side of the road" may also be as common as Portra 160 in Fuji C41 in a Jobo 1520 resulting in uneven agitation along the film edges. Maybe not drive a corvair altogether?

 

[Sirius Glass]

Indeed, and poorly is not just "insufficiently", but mostly "inconsistently across the film surface".

Furthermore, the "corvair on the wrong side of the road" may also be as common as Portra 160 in Fuji C41 in a Jobo 1520 resulting in uneven agitation along the film edges. Maybe not drive a corvair altogether?

I never drove a Corvair in pieces. Most people drove them assembled or in your terms 'altogether'.

 

[bluechromis]

Several years ago I came across a post in a thread on agitation by Prof. H. Lynn Jones who I believe was the chair of the Photography Dept. at Austin CC in TX. He did extensive testing of the various methods of agitation and concluded that there were only minor variations in density between the two methods while adding that the Dobro Method (an instructor at Brooks) proved to be the method providing the most uniform densities of any spiral tank method. I recall that it was a formal in depth study that was conducted with necessary instrumentation. He described the Dobro method as twisting action with an inversion that he was unable to visually put into words. This is the only formal testing that I have ever encountered. I was hoping someone on the forum might have found others.
I can't find the actual post discussing the actual test measurements but I did find a paper he wrote that references the tests. I believe that the Professor passed away sometime in the last year or two.

Here is the link to his paper: https://www.mr-alvandi.com/downloads/film-and-processing/black-and-white-developing-films.pdf
(pp. 10)

I came across an older article in Practical Photograhy (7/62) by John Hobbs titled, "A Practical Test: Agitation". I tried to attach it, but it said the file was too large. His tests used defunct film stocks like Verichrome, so is uncertain how findings apply to modern materials. It was more about frequency of agitation. But the overall conclusion was that style of agitation didn't make that much of a difference as long as there was some agitation. This seems to be a theme with agitation tests.

 

[bluechromis]

I had heard that some of the problems in development in tanks came about from heavy materials like bromides sinking down and leaving streaks. So it seemed obvious to me that he best way to combat this is to turn the tank upside down and make the stuff move the other way. But I learned that the first generation of Patterson tanks could only be used with swizzle stick, not inversion. Plenty of people still use the swizzle stick with acceptable results.

For a number of years I helped the instructor of college photo class. He made the students use the figure eight motion agitation, I think, because he wanted to avoid spills when tanks were inverted. We didn't see gross problems with uneven development. This was not a systematic test and could be argued that other agitation methods have subtle advantages. If my original assumption had been correct there ought to have been a bigger difference between inversion and non-inversion. My conclusion from this was that horizontal movement must create complex turbulence patterns that are roughly as effective as inversion. The point is, that our logical assumptions don't always pan out in practice. I remember the PE saying that it was generally best to test assumptions experimentally because of the difficulty of predicting how things would play out.

 

[bluechromis]

I'm pretty sure it's Paterson, not Ilford, that recommends using the agitator only at the beginning of the process. It never occurred to me to risk a roll of film by ignoring what sounds like very reasonable advice.

I agree that Paterson recommends swizzle agitation at beginning. I have heard that the greatest problems with uneven development occur early in development. So there is a great need have the film in contact with the developer uniformly right at the start. It takes me a bit longer to make sure the Patterson lid is firmly on and start inversions than to use swizzle stick. Nothing is worse than having the tank leak when tipped. So I suspect that the reason Patterson recommend swizzle at first is because it is fast.

At one point, I had striations on my negatives that I traced to pouring marks, which happens early in development. Some say pouring marks don't happen with modern film, but I had them. Both swizzle stick and inversion methods both have the film exposed to the developer unevenly because of the time it takes to fill the tank. What Kodak recommends instead is, in a dark area, to drop the film into a the tank already filled with developer which exposes all the film to the developer at once. This method eliminated my pouring marks. The differences between inversion and rotary agitation may turn out to be less than imagined. Kodak's recommended method of loading the tank may be a more important factor in the critical early moments of development. It also gives a precise start time and reduces chance of bubbles on the film. Yes, it is more of a hassle to load in the dark and people may feel that the don't have problems with pouring developer over film. But I have never heard anyone say the drop method could be bad. So at worst it doesn't matter and at best it does have a benefit.