Agitation: Inversion count vs. Time

[PatrickMP]

<p>I have been trying to recreate my darkroom process flow after being out of it for quite

a while, and part of this includes standardizing everything from start to finish.

 

<p>I have a question on agitation though.

 

<p>I have two Patterson tanks, a big one (3x35mm) and a small one (2x35mm) which I

use for developing both 35mm and 120. When I do an inversion, I wait for all of the liquid

to completely flow to the other side of the tank. Of course, with the larger tank, this takes

longer. Thus, if I am inverting for "10 seconds every minute", I may get 1 more revolution

with the small tank than the large one, due to the volume.

 

<p>So, when people agitate, do they do so for number of inversions (4 inversions per

minute, 6 inversions per minute, 10 inversions first minute, 1 inversion every thirty

seconds after, etc. etc. etc.), or for time (10 seconds/minute, 60 seconds first minute, 5

seconds every minute there after, etc.).?

 

<p>I'm assuming that the one revolution difference b/t small and large tanks would have

an effect; over the course of 13 minutes that's an extra 13 inversions at the very least!

 

<p>(Of course, I could standardize different methods for both small and large thanks, but

I'd prefer not to go that route.

[bruce_karnopp1]

Trying to standardize procedures is a worthwhile project. After 50 years, I have gone to a horizontal agitation system. I use a Unicolor agitation system. With the Paterson tanks, I had to modify a 4 inch plastic pipe so I could use my smaller tank. I use an Uncle Ben Rice can for my Jobo 2521 tank for 4X5. Times are about 15% shorter because of the constant agitation.

 

I got the Unicolor system on ebay for $5.

 

Next I bought a Jobo Tempering bath for all the chemicals. In my basement, this keeps everything at 20 degrees C.

 

The idea is to have every roll and sheet get the same treatment. All I have to do is to figure times for the films I use. And then everything is consitant. There are a lot of parameters in B&W photography. It is great to have at least part of the system predictable.

[paul_hoyt]

Patrick,

 

When I used to develop 35mm and 120 in tanks, I used the following procedure. I would soak my film in water for at least two minutes. When the developer is added to already wet film, it is suppose to displace the water in the film at a more even rate than soaking into dry film. Some do not believe in pre-soaking film, but it always seemed to work for me. I had very evenly developed negatives, great consistency with exposure/development. Pour out the water and tilt the tank to a 45 degree angle for the addition of developer. Start your timer and pour in the developer. The 45 degree angle will let the air escape as the liquid is being added; there should be no bubbling or gurgling. Put the cap on the tank and with the cap in the palm of your hand and the fingers over the lid onto the barrel of the tank, invert the tank, and keep inverting the tank until the sweep hand on your timer indicates 1 minuet has passed since you started. Each inversion should take a second. Palm up, palm down should take 2 seconds. The inversions let the bubble in the tank move from top to bottom and mix the developer to keep it homogeneous. At the 1 minuet mark you need to dislodge the bubbles that may be on the reels or trapped in the film. Most people rap the tank on a counter top; I read an article that suggested shaking the tank is better. Rap or shake is up to you. If you decide to shake, move your hand back and forth very quickly so the bottom of the tank moves between 7 O?clock and 5 O?clock at least 4 times. Every 30 seconds until development is completed, invert the tank 4 times and rap or shake. This should take about 5 seconds to complete. It did not seem to matter if I was developing 1 roll of 35mm film or 2 rolls of 120. Make sure you have a developing time of 6 minutes or more.

 

Paul

[patrick_gainer]

It's somewhat a matter of superstition. Once you have decided on a procedure, modify some aspect of it or another that you think might be critical and see if it really is.

 

When something would go wrong with something I was doing, my Daddy used to say "You didn't hold your tongue right." Now he was a Doctor of Philosophy and Philology in English Literature by decree of St. Louis University, so he should have known, so be sure you hold your tongue right. It may take some experimenting to find the right way to hold it, but once you do, stick to it.

[eric merrill]

Patrick:

 

My vote would be that it doesn't matter. Personally, I go with the easiest way possible between two choices that deliver the same end quality.

 

It's easier for me to agitate for time periods than to count inversions. So that's what I do.

 

I think you would be hard pressed to spot differences in the final print whether you agitated for 10 seconds/minute or 11 seconds...a 10% increase. That said, I'd try to be as consistent as possible. But don't drive yourself nuts over something like this.

 

 

Eric

[jay_de_fehr]

The development cycle is the only part of my film development process that I time; for the rest, I count inversions. For example; after the development time has elapsed, I pour out the developer, and fill the tank with water, invert 5X, dump, invert 10X, dump. Then I pour in the first fix, invert 10X, pour back into jug, pour in second fix, invert 10X, pour back into jug. Then I use the Ilford rapid wash sequence of 5/10/20 inversions. Then Fotoflo for a minute or so, and hang to dry. My process differs from the norm mostly in the fixer I use, which is a neutral pH, very rapid TT fixer Ron Mowerey calls Superfix. I probably wouldn't want to count inversions for several minutes of fixing.

 

Jay

[loren_sattler]

Kodak has some excellent information on small tank processing of B&W film. See following page in the professional section of the Kodak web site: http://www.kodak.com/global/en/professional/support/techPubs/edbwf/edbwf.jhtml#84930

[chris_waller]

Paterson tanks are very efficient at circulating the chemistry and so I keep agitation to a minimum.

 

My agitation regime is four inversions in the first 30 seconds then one inversion every 30 seconds after that. When I invert I count as follows:- invert-2-3-4-and-return, which takes about 5 seconds.

[johnny t. le]

i use the jobo method of inverting every 10 sec for the first min and then once every min.