How much chemical do you use?

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Originally Posted by Trevor Crone

As a matter of course when using Paterson System 4 Universal tanks I use a min. of 350 ml for 35mm film and 600ml for 120 film.

This is to allow for possible upward movement of the reel even with the retaining clip in place, and to prevent uneven edge development caused by 'frothing' of the developer.

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Something to consider as an alternative is having some lengths of PVC tubing to take up the slack at the top. An eBay seller shipped me a pen packed in a PVC tube once, and by nice coincidence, the tube closely matched the shaft diameter of my Paterson tanks, so I chopped it up into short spacers, and, voila, no more rising reels.

I wind up using 600ml for 120 film anyhow because I use XTol 1:2 with two rolls on a reel with a minimum of 100ml stock per roll. I still have a couple of rolls with a thin edge where the reel rode up the shaft prior to my using PVC spacers.

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Originally Posted by cao

Something to consider as an alternative is having some lengths of PVC tubing to take up the slack at the top. An eBay seller shipped me a pen packed in a PVC tube once, and by nice coincidence, the tube closely matched the shaft diameter of my Paterson tanks, so I chopped it up into short spacers, and, voila, no more rising reels.

I wind up using 600ml for 120 film anyhow because I use XTol 1:2 with two rolls on a reel with a minimum of 100ml stock per roll. I still have a couple of rolls with a thin edge where the reel rode up the shaft prior to my using PVC spacers.

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Thanks Cao.

I've just started testing with just spiral agitation and to abandon the inversion method altogether. I use PMk pyro and Pyrocat-HD; so far the results have been excellent and very consistant. Agitation is continuous for the first minute with 5 second spiral agitation every 30 seconds thereafter.

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Originally Posted by jlpape

My question is if you really should put in more than the
minimal amount to have enough chemical present to properly
develop the film (i.e. small amounts get used up and give
inconsistent results).

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Solution volume and amount of chemistry present are
two different but interrelated matters. For example using
Rodinal at 1:100 dilution only 2.9 ml of the developer are
present; a questionable little amount. At twice the
volume same dilution 5.8 ml are present; plenty.

D-76 is another matter. At 1:1 dilution there is plenty
of chemistry. Perhaps 1:3 enough. I use chemistry very
dilute and so use solution volumes greater than minimal.

So it might be thought there are two minimal limits;
a minimal solution volume, and a minimal amount of
chemistry. Dan

Many thanks to all that replied. Great idea to use the tubes to prevent the reels from slipping during development.
Jim

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Originally Posted by jlpape

Many thanks to all that replied. Great idea to use the tubes to prevent the reels from slipping during development.
Jim

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I have read somewhre (can't remember were) that, when you use a 2 reel tank of Patterson or Jobo, and only use one reel to process say 1 35mm film, you better add an empty reel. I think it was to prevent excessive turbulence, but it will also avoid that slippage problem mentioned..
I always try to use the smallest tank possible for processing film, and if not possible (Jobo) add an extra empty reel to the tank.

Best,

Cor

Whether or not you use more than the minimum amount of developer to cover your reel depends on the developer you use and its dilution. The rule I use when experimenting with a new developer or with extended dilutions - use at least 100ml of the stock solution (ex. D76) per 80 sq in of film or 100ml of the lowest dilution for which the manufacturer provides times (ex. Rodinal 1:25). Using these guidelines I don't believe I have ever underdeveloped a roll for lack of active developing agent.

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Originally Posted by jlpape

Many thanks to all that replied. Great idea to use the tubes
to prevent the reels from slipping during development. Jim

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I process 120 one reel one liter tank one half liter solution.
The reel goes thud at top end and clang at bottom. Dan