soaking in water before processing?

[Tom Hoskinson]

Tom, once again you prove what I have long known you are full of bulls---

your obediante servant,
Charlie....................

Wow! I must have hit a raw nerve! Sorry, Charlie!

[Dave Miller]

What’s this bulls stuff we are supposed to pre-soak in?

[Keith Tapscott.]

It's certainly the route followed by John Tinsley in his book "The Rotary Processing Manual" when he covers B&W film processing in a Jobo. Apart for the benefits mentioned in the other replies to this thread, his claim is that it exactly cancels out the reduction in development time recommended for rotary processors. So he made no reduction.

For what it is worth I recently tried rotary processing minus any pre-wash for Delta 400 at ISO 250 with Perceptol and found that my negs were thin. Most prints were at grade 4 and even 5 to get the contrast required.

I have concluded that Ilford's recommended reduction of 15% for rotary processing is too much. I reduced this to 10% for FP4 and have found this to be still too much although it was better.

Ilford do not recommend pre-washing but based on my findings above and others comments on the benefits from actual seasoned practitioners, it seems as if a pre-wash and no alteration to development times may be the route to go for rotary processing at least.

Pentaxuser

I have found with the 4x5 sheets that I process in my Jobo CPA-2, that the standard small tank times work best. That is with D-76 diluted 1:1 and with out a pre-rinse using a 2563 Multitank which allows up to twelve sheets to be processed. I acknowledge that personal preferences play an important role and it depends on how you like your negatives. For 35mm & 120 rolls, I use either a Paterson or Jobo 1500 series tank with intermittent agitation, although on the occasions I have used rotary processing with roll films I found again that I prefered the films developed to the small tank times and again with out a pre-rinse.
I remember reading an article by Roger Hicks ( if my memory is right) that films like T-Max P-3200 TMZ & Delta 3200 Delta have additives in the emulsion which help to optimise the speed yield and a pre-rinse could cause a detrimental loss of emulsion speed yield.
I use the Jobo mostly for the E-6 process.
I also have the same book by John Tinsley.

[pentaxuser]

Keith. I know this may not be helping Matt in the sense that the thread is now catering for two schools of thought on pre-soak but for my benefit I believe you are saying that even without a pre-soak, Jobo processing benefits from following normal inversion development times. In summary: FollowTinsley's advice on times which is to use, in my case, Ilford times based on inversion agitation but not follow his advice on pre-soak.

Have I got this right?

My only concern is that I had a third film to develop which was HP5+. Courage failed me and I reverted back to Ilford's inversion agitation times and found that I got good
negs which are printing fine at grade 3 which is about right for a colour head diffusion enlarger(Durst 605M).

However unless continuous rotary agitation has no effect at all then my fear would be that using normal inversion agitation development times with the Jobo would result in
too much contrast.

On the other hand unless the resulting negs were way over the top then if rotary processing resulted in negs that needed grade 2 printing instead of grade 3 then what would be the adverse consequences of this, if any?

I should add that my HP5+ was developed using inversion agitation at 1:3 in Perceptol and this may not be a good basis on which to speculate on the effect of
rotary processing at inversion times because Tinsley does say that this kind of dilution is not ideal for rotary processing.

I presume his statement is based on there being too little Perceptol at 1:3 in a rotary processor. The tank only needs 140ml so at 1:3 this is only 35ml of stock solution.

Finally for others interested in rotary processing Tinsley who lists very few films and developers mentions " The Black and White Handbook" published by Jobo. The book covers processing recommendations and effective film speeds for over a hundred film/developer combinations. It is available as part number 4191.

Does anyone know where this may be obtained?

I don't know if Keith will agree with me but I found the Tinsley book very helpful for anyone wanting to try Jobo processing. He covers colour neg, colour reversal film processing as well as RA4 and Cibachrome printing.

The ISBN is 0-902979-11-6 and the publisher was R Morgan Publishing, PO Box 11,Chislehurst, Kent BR7 5RH.I have no idea whether it is still obtainable as it was published way back in 1992. The way things have gone in the last 13 years in photography this is unfortunately a lifetime ago.

Thanks

Pentaxuser
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