Shaken, not Stirred?

SodaAnt · Aug 4, 2023

I'm just getting back into darkroom work after many years away from it. When I used to develop 35mm film years ago I used Paterson tanks and reels and always agitated by spinning the stirring stick that comes with the tanks back and forth. I developed hundreds of rolls of 35mm that way and didn't notice any issues.

Now that I've gotten back into it, developing both 35mm and 120 film, I've read that the way to agitate with Paterson tanks is by inversion. What are the benefits of inversion agitation versus twirling the stirring stick back and forth? The big advantage of using the stick is there's no need to spend time getting the top lid on the tank and no chance of leaks while agitating. Am I missing something?

BrianShaw · Aug 4, 2023

You’re not missing anything in my opinion. I stir and/or wiggle-waggle. Never had an agitation-related problem. Perhaps the only issue with stirring is the possibility of forgetting to thump for bubble release. Shaking is reserved for cocktails with fruit juice and

Donald Qualls · Aug 4, 2023

I've done both swizzle stick and inversion, as well as "rocker" agitation with a Yankee Agitank -- done correctly and carefully, all can produce good results, as can continuous roll agitation. The gold standard is/was nitrogen burst in a deep tank...

MattKing · Aug 4, 2023

Well, the Paterson instructions tell you to only use the twirl stick for the initial few seconds, so if you believe in following the instructions .....
Inversion helps randomize the movement of fluid and helps ensure that you avoid uneven distribution of development byproducts in the tank.
When I help newbys learn this stuff, I demonstrate with an agitation procedure that ensures that the tank is both inverted and twisted at the same time. And I tell people that they should be able to hear and feel the developer tumble and gurgle as they twist and invert.
The Kodak recommendations prescribe very active agitation for the first 30 seconds. I believe that helps ensure that no bubbles form and that the emulsion is fully wetted. If you use the twist agitation at the beginning - say for 30 seconds - most likely that will accomplish the same thing.

SodaAnt · Aug 4, 2023

MattKing said:
Well, the Paterson instructions tell you to only use the twirl stick for the initial few seconds, so if you believe in following the instructions

The two Paterson tanks I've bought recently didn't include any instructions. Only the tank itself in a cardboard box.

Right after I pour the developer into the tank, I rap the tank hard on the tabletop a few times to dislodge any air bubbles adhering to the film before I start twirling the stick. I've always thought inversion agitation had more of a chance for air bubbles on the film because parts of the film are exposed to air on every agitation cycle.

If I try inversion agitation, how vigorous should it be? I've seen YouTube videos where one guy violently shakes the tank as if he were making a Martini. That seems like overkill to me.

BradS · Aug 4, 2023

I've used the Paterson Super System 4 tank for 30+ years and have always either twisted the swizzle stick or picked up the tank and kinda waved it in a lazy figure eight. Never had any issues. I don't do inversion. Too many issues - bubbles, the reel migrating up the center post, bubbles, leaks, bubbles, etc...

MattKing · Aug 4, 2023

Grab the tank in both hands - one hand on the top, the other on the bottom.
Start with your hands at the same height and the tank level and on its side.
Turn your hands and arms so that the tank is reversed - where the top was, the bottom will be now, and vice-versa, and then return the tank back to where it started by reversing the movement. Note how the tank naturally twists as it turns over, and listen and feel how the solution tumbles and gurgles.
That single over and back process is a single inversion cycle.
If you do two of those in 5 seconds, that is the sort of agitation I recommend.
Kodak suggests starting out doing those faster for the first thirty seconds, and then at that rate for 5 seconds every 30 seconds. Ilford suggests doing those for longer at first, and then for 10 seconds every minute. Pick one, and use it consistently.

Donald Qualls · Aug 4, 2023

SodaAnt said:
I've always thought inversion agitation had more of a chance for air bubbles on the film because parts of the film are exposed to air on every agitation cycle.

Once the film is fully wetted, there's effectively no place for bubbles to lodge other than in the reel grooves (which are outside the image area for 35 mm and larger film, generally). One exception to this is if there is little to no developer above the upper film edge, then that edge will be prone to an uneven edge that gets less or no development, and it will often show bubble imprints.

Flighter · Aug 4, 2023

From the Paterson System 4 instruction book

oxcanary · Aug 5, 2023

For the last 20 years I have used the Paterson swizzle stick. Very happy with results. Also easier to standardise practice with standard swizzles and a standard number of them.

pentaxuser · Aug 5, 2023

Flighter said:
From the Paterson System 4 instruction book
View attachment 345728

View attachment 345727

Thanks I had not realised that the official Paterson agitation method was as gentle as this. So a few twists with the stick then nothing for a minute then only one agitation per minute. In say a 10 minute development time this is a few seconds twisting and then 9 inversions only Quite far removed from either the Ilford or Kodak regime which in turn are quite far removed from the guy making cocktails

Did he have "Going loco down in Acapulco" playing while he was doing it?

Slightly more seriously, maybe just maybe, success can be achieved with quite a range of methods

pentaxuser

Flighter · Aug 5, 2023

I read somewhere, it may have been a posting here, that the aim behind the twizzle stick was to reduce the delay between pouring the developer and starting agitation as it could be done immediately pouring stopped without the delay of putting the cap on (assuming of course that the twizzle stick hasn’t rolled way under something in the meantime).

cmacd123 · Aug 5, 2023

like so many other things, the way that works for you is best. I use the JOBO 1500 system which does not have a stirr stick and I do a couple of inversions every minute. Advantage of inversion is that you get different developer on the film each time while the swizzel stick is sometimes accused of causing Stale developer to "Drag" and thus blamed to cause streaking.

AnselMortensen · Aug 5, 2023

I alternate between swizzle-stick and inversion....for a 10 min. developing time, 5 times with swizzle, 5 times inversion.

koraks · Aug 6, 2023

My main issue with the twizzle stick thingy is that it tends to get stuck. It's annoying when that happens. Other than that, it's always worked fine for me. No issues with uneven development because of it. YMMV. For me, the whole thing boils down to:
* Do you like the twizzle stick? --> Use it.
* Does the twizzle stick give you problems? --> Don't use it.

cmacd123 said:
the swizzel stick is sometimes accused of causing Stale developer to "Drag" and thus blamed to cause streaking.

Yes, the accusation is common. Another question, of course, is in how many instances it's also substantiated. I guess that one is difficult to figure out. I never bothered trying to figure it out because the decision-making process outlined above seems to be a decent workaround.

snusmumriken · Aug 6, 2023

I do exactly what the Paterson instructions say. When twisting, the backwards and forwards part is important, because you probably don’t remember which way your spirals are facing. Twisting for the first few seconds means the chemical gets to the film evenly straight away, rather than waiting while you fumble with the lid. (The instructions posted above show the early System 4 tank, which had a simple small push-on lid. The later Super System 4 has a wider opening allowing faster pouring, but it takes a little longer to get its wider lid seated all the way round, so the twiddle stick makes even more sense.)

During inversion, it takes time for the chemical to flow around the outside of the tank to the lid, and likewise back down through the funnel. Two inversions in 5 sec sounds about right. There has been some previous discussion on the forum about foaming, which seems a good reason not to be too vigorous with agitation.

When you tap the tank to dislodge any air bubbles, don’t be too rough with it: it is possible to break the flange on the bottom edge (I have).

faberryman · Aug 6, 2023

This is just minutia for the sake of minutia. Just follow the instructions and do whatever you do the same way each time and you will be fine.

SodaAnt · Aug 6, 2023

snusmumriken said:
When you tap the tank to dislodge any air bubbles, don’t be too rough with it: it is possible to break the flange on the bottom edge (I have).

I put a folded towel down on the counter top and rap the tank on that.

snusmumriken · Aug 7, 2023

SodaAnt said:
I put a folded towel down on the counter top and rap the tank on that.

Yes, so do I - now!

JPD · Aug 7, 2023

I invert the tank by turning the wrist instead of the arm like on the pictures. Getting leaking chemicals on your arm and shirt is a bad idea. Dermatitis from metol, bleached skin spots from hydroquinone, cancer from benzenes...

lamerko · Aug 7, 2023

Sometimes I have problems with the jobo 1500 - the system does not have an agitator and the only way is with inversion. The problem is that sometimes gas is produced when changing from alkaline to acid, causing my cap to pop off while doing an inversion…

faberryman · Aug 7, 2023

lamerko said:
Sometimes I have problems with the jobo 1500 - the system does not have an agitator and the only way is with inversion. The problem is that sometimes gas is produced when changing from alkaline to acid, causing my cap to pop off while doing an inversion…

What gas is produced with photo chemicals going from an alkaline to an acid in sufficient volume to cause the cap of your Jobo developing tank to pop off.

lamerko · Aug 7, 2023

faberryman said:
What gas is produced with photo chemicals going from an alkaline to an acid in sufficient volume to cause the cap of your Jobo developing tank to pop off.

I guess there could be different situations, but specifically in my case, sulfur dioxide was generated when I transferred the developer into a sulfuric acid stop bath. In particular in the ECN-2 process. Kodak's documentation gives startling figures for the volume that is being generated...

koraks · Aug 7, 2023

faberryman said:
What gas is produced with photo chemicals going from an alkaline to an acid in sufficient volume to cause the cap of your Jobo developing tank to pop off.

Carbon dioxide.
The caps on my Jobos pop off much of the time. It's one of the reasons I use an acid stop after C41 developer. Going from dev straight to bleach has cost me a lot of bleach already.

lamerko said:
sulfur dioxide was generated

Nah. Sulfuric acid + carbonate will give sulfate, carbon dioxide and water. It's the carbon dioxide that pops off the cap.

faberryman · Aug 7, 2023

I use stainless steel tanks. I have never had the cap pop off. When I take the cap off to dump chemicals, I never hear a burp or feel a puff of air. Maybe they are not air tight.

Shaken, not Stirred?

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