to agitate or rotate?

[santino]

Hi!

Is there a big difference in agitating film or rotating it? always when I agitate it in my Paterson tank the developer spills a bit out (it isn't really sealed by the rubber cap) and if you recommend agitation, what motion is the best to agitate? turn it upside down and back?

thanks 🙂

 

[sleepyhead]

I agitate by holding the tank in my hand and twisting my wrist. I'm skeptical that rotation would provide enough agitation, but this might depend on what developer/film combination you're using. The best thing would be for you to test rotation (i.e., avoid spilling), and see if you're getting good, consistent, even development. If so, then you're fine. If not, I would recommend getting a tnk that doesn't leak.

Good luck

 

[matti]

I have no experience with rotating. But I can tell you how not to spill:

Don't close the rubber lid completely on the tank, then push down the middle, so you push out air and then close the lid. Now you created some small vacuum in the tank and it won't leak a drop!

Works for me anyway.

/matti

 

[ClaremontPhoto]

Inversion about once a seond for the requisite time, followed by tilting the tank and tapping it on the countertop to dislodge air bubbles.

I haven't actually done it for years but it used to work for me.

 

[Andy K]

Chances are you'll get as many answers as there are photographers!

I agitate by one complete inversion every thirty seconds (an inversion taking about five seconds), if developing two films at once. If developing only one roll, Itilt the tank to about 45 degrees and then rotate it a couple of times every thirthy seconds.

 

[Ronald M]

Maybe you can get rotation to work, but inversion is the recommended method. Rotation is to be used only right after the developer is poured in per the instructions that come with the tank. Use 1/3 turn back and forth for 20 sec.

If you get less density in the center compared to the edges, rotation is not working for you.

People store the lids on the tank and stretch them causing a problem. Leave it off

 

[jano]

I found by rotating either by the given doohickey or with the wrist, you can get sprocket-hole leaks or incomplete agitation, especially for medium format, unless you fill up the tank with a bit more than recommended developer/fixer/etc.

 

[bmattock]

I agree that everybody has their pet way of doing agitation when it is required. In fact, it is hard to stop some photographers from doing agitation when it is not required or even desired (like when using Diafine, especially solution A).

It is important to remember two things. First - the goal of agitation is to get fresh developer onto the film emulsion and to get spent developer away - this allows thorough development, and prevents uneven development. Second - more important than how you do agitation is that you do it as close as possible to the same way every time.

If *your* way of agitation is to rotate the tank (I would NEVER do that, LOL) then do that - the same way every time, for the same length of time, as often as recommended or that your experience has suggested works. Don't vary it. That's the key - repeatability.

For what it may be worth - I invert if I am using a tank that supports that - and if not, I use the agitation method suggested by Kodak on their website - moving the tank in a short arc on the table top and turning it only slightly while so doing. Ever twist a glass of liquid and notice that the contents didn't turn? Same thing is happening inside the tank when you twist it to agitate - nothing. The tank turns, the liquid doesn't. Your goal is to get the liquid to move. How you do that is more a matter of personal taste and doing it the same way every time, IMHO.

Best Regards,

Bill Mattocks

 

[ruben]

I too use Paterson tanks. spilling a bit sometimes. Therefore a hold them from the top with a fabric to absorb the leak.

My secuence, for all developers, for the last 10 years has been:
a) continuous invertions for the first 30 seconds
b) each additional 30 seconds I perform the following:
1) 3 invertions (down and up is 1) lasting not more than 5 seconds
2) when landing the tank I turn it a quarter of turn around (to guarantee the next invertion will be from a different angle.
3) Besides the quarter of turn I make a BANG !, meaning a slight knock of the bottom of the tank against the working table, in order to disengage any possible bubbles.

Cheers,

Ruben