Shaken, not Stirred?

[koraks]

With my Paterson tank, I also never get any burping. Its cap apparently doesn't seal nearly as good enough for it to happen. The Jobo caps are a snug fit.

 

[lamerko]

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

I'm not a chemist and don't know what actually interacts with sulfuric acid, but the documentation states the following:

Install an exhaust over the stop tank, since developer carried over into the stop generates sulfur dioxide. The exhaust system should produce an air flow of 175 ft3/min (5 m3/min) for every square foot (0.09 m2) of solution surface and provide 50 to 75 ft/min (15 to 23 m/min) control velocity over the surface of the tank.

 

[Sirius Glass]

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.

I have had a little leakage from the top of stainless steel caps on occasion, not often.

 

[faberryman]

I have had a little leakage from the top of stainless steel caps on occasion, not often.

Well, sure, that's part of the charm of stainless steel tanks.

So you Jobo guys, when the cap pops off does it sound like you are opening a can of Coke? Seems like a lot of gas is being generated to cause the cap to pop off. Seems like you wouldn't need to agitate. Seems like there would be a natural nitrogen burst effect going on in there.

 

[Sirius Glass]

Well, sure, that's part of the charm of stainless steel tanks.

So you Jobo guys, when the cap pops off does it sound like you are opening a can of Coke?

Only when opening the Expert Drums which needs a pump to pop the top off. Evidentially prying the top off is bad for the drum, and it does not come off easily that way.

 

[mshchem]

Only when opening the Expert Drums which needs a pump to pop the top off. Evidentially prying the top off is bad for the drum, and it does not come off easily that way.

I give the expert tank a big hug then blow into the opening until the lid blows off. Fast and easy.

 

[koraks]

I'm not a chemist and don't know what actually interacts with sulfuric acid, but the documentation states the following:

A little bit of sulfur dioxide is generally formed due to developer carry-over into an acid fix; this appears to be mostly because of sulfite breaking down (it's unrelated to the acid of the stop; it happens just as well with acetic and citric acid). However, the main volume of gas produced is carbon dioxide. This is what makes the lid on Jobos pop. If it was sulfur dioxide generated in those quantities, we wouldn't be able to safely work in a darkroom at all!

 

[Sirius Glass]

I give the expert tank a big hug then blow into the opening until the lid blows off. Fast and easy.

From what you posted, you can blow harder than I.

 

[mshchem]

From what you posted, you can blow harder than I.

Oh yeah, you know it!

 

[Donald Qualls]

I've never had trouble getting the inversion cap on a Super System IV in a couple seconds after pouring, and usually do so and start inversions immediately -- but for C-41 (because I replenish my Flexicolor and want to minimize oxidation of the developer) I use the swizzle stick throughout the 3:15 development time with good results.

 

[Craig]

Try an experiment with the Peterson tank: put in the usual volume you would use of developer, but use water instead. Put in the centre core and a reel, and leave the lid off so you can see the water. Twiddle as you normally would and observe the water. When I did it, the water rises considerably and tumbles over onto the reel. It was quite a vigorous agitation.

When I am finished twiddling, I also stop the reel abruptly. The developer continues to flow past for a while. I also turn so the open end of the spiral is going into the fluid, so the motion will push it along the spiral and into the core. It works for me.

 

[mshchem]

I've never had trouble getting the inversion cap on a Super System IV in a couple seconds after pouring, and usually do so and start inversions immediately -- but for C-41 (because I replenish my Flexicolor and want to minimize oxidation of the developer) I use the swizzle stick throughout the 3:15 development time with good results.

Good idea. I developed color film in Paterson tanks for decades, never dawned on me to swizzle only. I have a couple Jobo machines now, I'm reluctant to replenish black and white developer let alone color. I replenish bleach, I replenish E6, but not 1st or color developer.

Amazing how well a water bath and a thermometer work. Probably, almost a certainty more repeatable from agitation and temperature control than the JOBOs. Swizzle and thermometer are closed loop, Jobo is not.

 

[Donald Qualls]

I developed color film in Paterson tanks for decades, never dawned on me to swizzle only.

I've only done it because I replenish. If you're reusing with time added (canonical operation with most kits) the chemistry life is based on the assumption you'll use inversion anyway. For Flexicolor, however, replenishment rates and the indefinite life of the tank solution are based on the relatively low aeration of an automated processor. Swizzling is closer to that than inversion, probably.

 

[mshchem]

I've only done it because I replenish. If you're reusing with time added (canonical operation with most kits) the chemistry life is based on the assumption you'll use inversion anyway. For Flexicolor, however, replenishment rates and the indefinite life of the tank solution are based on the relatively low aeration of an automated processor. Swizzling is closer to that than inversion, probably.

And swizzling is absolutely adequate agitation. I buy color chemistry in large volumes so I have plenty. Kodak (as you are aware) forbids replenishment of Flexicolor when using a Jobo (rotary) constant agitation.

 

[MattKing]

Kodak (as you are aware) forbids

I think it might be closer to "does not recommend"

 

[Donald Qualls]

closer to "does not recommend"

Which is effectively the same. If you complain about your results with Flexicolor and they find out you're replenishing with a Jobo, they might just hang up on you; they certainly won't pursue any sort of remedy even to the extent of replacing the "faulty" chemicals.

 

[cliveh]

Well, after doing a PhD in fluid dynamics, I would suggest swizzle stick and inversion.

 

[mshchem]

Well, after doing a PhD in fluid dynamics, I would suggest swizzle stick and inversion.

When in doubt introduce chaos. Swizzle, rattle and roll.

My Dad developed 100's of rolls with an old Elkay tank, all he had was a swizzle stick, and of course sliding the tank a bit, Kodak approved technique.

 

[Niglyn]

Well, I have been doing it wrong then.
I used a Jobo with the rubbery lid & was taught agitation for the first 30 seconds and then agitate for 10 seconds every minute. (a previous post asked about gas build-up. Jobo had a push-down bit in the lid, which could push up 7 expand, should internal pressure rise)

Agitation should be gentle, in an arc movement and also rotate tank. Each agitation followed by a tap to the worktop to dislodge bubbles.

Move on 30+ years and get a patterson tank, with a really stiff, difficult to fit lid.
So after watching 'shoot like a boss' ask if you are a twiddler....

I ensure the film is in the tank wound middle to outer clockwice. Then pour, tap and twiddle clockwise for 30s then twiddle for 10s every minute. Gentle twiddling.
I find twiddling far easier than having to mess about with the patterson stiff lid, there were no splashes of water everywhere from the water-bath (as tank stays in the bath) and contrast looked really good. I was instantly converted to twiddling.

I have an idea to make an auto-twiddler, using an Arduino driving a stepper motor. You can set total time & number of twiddles, initial twiddle time & subsequent twiddle times. Would also twiddle for stop & fix.

 

[Andrew O'Neill]

My favourite move with Mrs. Paterson, is the Figure-8. She doesn't like to spin or be flipped over...

 

[Fatih Ayoglu]

Unfortunately I have had issues with BW and C41 films when I have used the stick method (back and forth, continuously), it has created light strips, caused by unequal development, especially in sky areas. So now back to the inversion method.

When I have check closer, I have realised when using the stick, it does not mix the chemical in the tank very effectively, but that might be a problem of mine only, don't know.

 

[SodaAnt]

Unfortunately I have had issues with BW and C41 films when I have used the stick method (back and forth, continuously), it has created light strips, caused by unequal development, especially in sky areas. So now back to the inversion method.

When I have check closer, I have realised when using the stick, it does not mix the chemical in the tank very effectively, but that might be a problem of mine only, don't know.

Not my experience. Back before digital I developed hundreds of rolls of B&W in Paterson tanks and agitated only using the swizzle stick. I never had any detectible uneven development.

 

[Fatih Ayoglu]

Not my experience. Back before digital I developed hundreds of rolls of B&W in Paterson tanks and agitated only using the swizzle stick. I never had any detectible uneven development.

I’m jealous of you. Sadly I wasn’t lucky like you. Maybe your stick agitation was better than mine for some reason

 

[Craig]

Unfortunately I have had issues with BW and C41 films when I have used the stick method (back and forth, continuously),

Back and forth might be the problem. I only turn in one direction. That gets the fluid moving, then I stop the reel from rotating with the stick and the developer keeps flowing past the film.

 

[BrianShaw]

I twiddle back and forth 3 times, each time, slowly and seem to always get even agitation.