Just wondering who uses a water presoak, and of those who do, do you use tap or DI water? I always mix my solutions with DI water, my stop bath is running tap water, and I soak my film in DI water with Photoflo at the end. I've also been doing my presoak in DI water, but I was wondering if it would be ok to use tap water for this. I was worried that it may cause some ill effects in the developer, but there is such a small amount of it retained in the emulsion when it is transfered, that I'm not sure it would effect the large 500-1000mL developer. Any suggestions?
I didn't when I used stainless tanks. When I started using a JOBO, I noticed uneveness and air bells so I decided to do a pre-soak. Then I went to the JOBO site and saw that they recommend a very long pre-soak of five minutes so I went with that. Since then I read an article that said long pre-soaks have varying unpredictable effects on different films but I haven't returned to a short pre-soak as of yet.
I use tap water for the pre-soak for the same reason that you mentioned.
I always presoak in distilled water.
I don't use a water pre-soak, with one exception: MACO IR820. A pre-soak there is recommended by MACO to remove the anti-halation backing before processing. I use tap water.
Also, I have heard - I don't remember the source - that distilled water is not desirable in mixing developers, as some contain "sequestering agents" that - to some extent - "need" common impurities to "balance out" properly.
I have read advice by Ilford and Agfa against "pre-soaking" film ... that it lessens acutance and definition due to "swelling" of the emulsion before the developer has a chance to penterate and work its magic.
I have *NO* doubt that the last two remarks will spark a LOT of discussion.
With rotary processing I always pre-soak for five minutes in tap water. Pre-soaking is very important with this method of development when using staining developers like PMK, Pyrocat-HD and Rollo Pyro.
Tests have show that films react differently to different time pre-soaks. My understanding is that the five-minute time is based on the fact that nearly all films reach a similar equilibrium at about five minutes of pre-soak. This would presumbably be based on the fact that by five minutes the gelatin will have absorbed all of the water it can absorb.
As for the Ilford and Agfa advice that pre-soaking film lessens acutance I think that is just pure nonsense. I seriously doubt anyone could devise a test that would show this to be true with normal processing of film.
I lived in Houston right before I moved here, so I know the water is too hard, you will have dry spots if you use it for the washing, but will have no problem using it for developers. As a matter of fact in some ways it is good to use hard water as it contains Calcium Carbonate, which acts as a buffer in the developer. Dont waste your money on DI water, you wont see a difference.
I dont presoak, as far as I am concerned presoak is good for rotary developing to prevent surface tension from creating running channels, but I have had no problem with brush developing without presoak with Ilford FP4 and 400 TMY.
As they say your milage may vary.....have fun.
I recently presoaked some Efke R100, the first film I've presoaked in 20+ years, because the maker recommends it. I can see why - the anti-halation dye *immediately* discolored the water. It's far less tenacious than dyes on other films.
Then it occurred to me to try presoaking before development in Diafine. Since Diafine is reused repeatedly it can accumulate a lot of dye. I figured that presoaking might minimize that problem.
The first film I had available was TMY, notorious for retaining a tint after processing. Presoaking in our fairly alkaline tap water (from a rural well) didn't remove a significant amount of dye. It was very slightly tinted, but nothing like the pour-off from Efke R100.
I can see the advantage to presoaking for very short development times - 5 minutes or less - or for films *proven* to benefit from the practice.
But I don't plan to change my procedure of simply starting rollfilm development from dry.
This is from the Jobo quarterly Issue #3, (http://www.jobo-usa.com/jq/jq9403.htm). It seems to conclude that this topic is pointless to argue.
>>"JOBOís recommendation of a 5 minute prewet of B&W film is probably one of the most disputed suggestions we have made. It causes many people to choose up sides. Certainly many people have chosen to use the prewet, and are more than happy with the continued excellent results they obtain. They have made the other necessary adjustments, and their process is clean and consistent. The original suggestion came from Germany, with the statement that the H&D Curves were closer to the manufacturer's curves when we used a prewet with rotary.
Several technical writers/lab technicians in Germany disagreed with the idea of prewet. Using a JOBO processor they produced a list of films and developers, with processing times, NOT using prewet. We have tried some of these combinations. Every one which we tried performed beautifully. The chart shows what they produced.
More information on the effect of prewet comes to us in an article in the May/June 1994 issue of Darkroom & Creative Camera Techniques. Phil Davis (Beyond the Zone System) has an article entitled "How Prewetting Film Can Affect the Image". While Phil is not dealing with rotary processing in his article, his findings apply. To quote his conclusions, "In most instances, prewetting will influence image formation to some measurable degree. The probable result will be some increase in image density and contrast, and occasionally a slight boost in film speed. It is also apparent that all films are not affected the same way, and an individual film's response to prewetting may not be the same in all developers."
Of course JOBO has a track record regarding the use of the five minute prewet, but it is apparent that this type of information was not available when we established the blanket 5 minute approach. The best advice that can be given is to echo Phil Davis and Paul Schranz. They were writing 7 years apart, but have said the same thing. Iíll quote Phil Davis, "...it is a matter for the individual photographer to decide, so I leave it up to you to determine how prewetting affects the materials of your choice." What more can we say?"<<
There you go... clear as mud. Do whatever the heck you want. :)
I only pre-soak with staining developers such as PMK prior to using my JOBO.
I used to pre-soak before all my other developers but never noticed any difference over not pre-soaking, so I eliminated it to save time.
I had a number of discussions with Ilford (on the IlfoPro forum) and while they do not recommend a pre-soak they say it does no harm but extends the development time.
The ilford emulsions contain an agent that allows the developer to be absorbed quickly and reduces development time. The presoak removes this agent. So for rotary processing they recomend using the small-tank developing time.
I have always used a presoak whether using a small-tank or my Jobo, and have never had any issues. But then again using large tank development for sheet film I have never used a presoak and still worked.