How long do you presoak?

There are three reasons for presoaking:

1. Get the emulsion thoroughly saturated
2. Ensuring even development
3. For color film, bring the film and emulsion to the development temperature.

Sirius Glass said:

There are three reasons for presoaking:

1. Get the emulsion thoroughly saturated
2. Ensuring even development
3. For color film, bring the film and emulsion to the development temperature.

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1. Nowhere in any film manufacturers datasheets does it say film must thouroughly saturated before development. In fact Ilford say the opposite
2. Even film development doesn't require pre-soak. See 1 above.
3. Jobo ATL1500 only uses pre-soak for B+W film in its default programs and not for C41.

Sirius Glass said:

There are three reasons for presoaking:

1. Get the emulsion thoroughly saturated
2. Ensuring even development
3. For color film, bring the film and emulsion to the development temperature.

Click to expand...

RobC said:

1. Nowhere in any film manufacturers datasheets does it say film must thouroughly saturated before development. In fact Ilford say the opposite
2. Even film development doesn't require pre-soak. See 1 above.
3. Jobo ATL1500 only uses pre-soak for B+W film in its default programs and not for C41.

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I said that those were the reasons. C-41 processing on the Jobo processor recommends presoaking, however Jobo specifically says not to presoak for XTOL processing and for replenished XTOL processing.

Sirius Glass said:

I said that those were the reasons. C-41 processing on the Jobo processor recommends presoaking, however Jobo specifically says not to presoak for XTOL processing and for replenished XTOL processing.

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depends which jobo processor. It's requirement of the processor to mitigate how the processor treats the film and not a requirement of the film itself. I just want to get that point across so that people using inversion or dip and dunk tanks don't think its a requirement of the film itself.

I was referring to the Jobo CPA, CPA2, CPP, CPP2, CPP2+ et al

I presoak for three minutes in the ATL-3. I develop 120 in an inversion tank and I do not presoak for that.

MattKing said:

Three minutes.

This gives me just enough time to reach the correct level of spiritual oneness with the process.

And to double check that all my chemicals and measuring graduates are ready to go, as well as confirming the ambient temperature, for development time considerations.

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Matt,

Interesting! I also use my pre-soak time to get into the rhythm of agitating, etc., before putting the film in the developer, especially when I have tricky number of sheets in one batch.

RobC said:

now here's an interesting thought for all you people using pre-soak.

By pre-soaking, the water is absorbed into the emulsion and the emulsion swells. The water slows down/inhibits the developer from getting to the silver halides so takes longer for development to happen as it needs to leach into the emulsion instead of it being sucked up by the emulsion.
This means that the halides at the surface of emulsion get more development than those deeper into the emulsion. So you get more surface development rather than even development through the thickness of the emulsion.

I wonder what difference that makes and how long it takes to leach into the full depth of emulsion. Ilford say they have wetting agent incorporated into their films, presumably to help developer soak into the full emulsion depth evenly. Just another little thing to consider and discuss.

Note: I do realise Jobo recommend a pre-soak but that is because of the nature of their processor and how it applies the developer to film and not the nature of the film itself.

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Of course, we who incorporate a pre-soak into our routine have adjusted (tested) our development times accordingly. For the reasons you state, development will take longer starting with a water-saturated emulsion than without.

While a pre-soak is not necessary per se, if we do use one, for whatever reason (i.e., keeping the sheets from sticking together in the developer when tray developing), then making sure the emulsion is completely saturated before the film hits the developer seems logical to prevent possible differential absorption/diffusion of the developer by/into the emulsion. There must be data on that somewhere, but I can't seem to find it. Three minutes seems to work for the films I use.

If, and it's a big if, pre-soaked films when completely developed have more surface development than deep development when compared to film developed without a pre-soak, then that should (theoretically) help acutance some... I kind of doubt that this is the case, however. Much more likely is that developer onset is delayed a bit but compensated for by extending the time (assuming equal CI of films developed with and without a pre-soak).

Oh yes; I omitted one important reason for a pre-soak in my previous post: bringing all the tanks, etc. to the correct processing temperature. This, I believe, is why Jobo recommends a soak.

Best,

Doremus

Its interesting that Ilford has wetting agent incorporated in the films ...

Coz I presoak for 4 mins with 0.2ml of PhotoFlo per 300ml of the distilled water ...

I reckon the PhotoFlo helps remove finger grease and haven't had a failure yet ...

I don't.

haziz said:

I don't.

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But Katmandu.

darkosaric said:

So,

I don't want to start another flame war of presoak or not - I am just interested how long do you presoak? I don't presoak 35mm, but 120 films I do, for 30-45 sec.
I saw on couple of threads that some presoak for 5 minutes. Why so long? How long should one presoak?

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I used to presoak for 1 minute. I don't presoak any more because my development times are fine. You want to make sure the emulsion is all all swollen with water so the initial developer action slows somewhat. This will increase your development times which may be handy if you are nearing the 4 minute mark.

RobC said:

For zero seconds.

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so fill and drain at the same time?

Although I never pre-soak black & white film, I can understand the reason for pre-soaking colour film, where process temperatures are so critical.

I have problems with Ilford films when I pre soak. I pre soak everything else for 2 minutes. My films are 120 4x5 and 8x10.

I only presoak TMY-2 and Rollei IR films when using BTZS tubes. Helps remove that pesky blue dye. Three minutes then slip them directly into the tube. The only time I presoak other films such as HP5 or FP4, is when I am giving them two-bath development in pyrocat-hd.

3 minutes.

I presoak for five minutes before stand developing.
For regular development times, I do not.

cliveh said:

Although I never pre-soak black & white film, I can understand the reason for pre-soaking colour film, where process temperatures are so critical.

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+1

cliveh said:

May I ask why you presoak 120, but not 35mm? Not that I have ever presoaked a film, but why should the format size change your MO?

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I presoak 120 only. For 40 years I didn't have any unevenness with 35mm (Jobo inversion tank) but 10 years (maybe longer) ago I ventured into 120 and found that I had some discs of slightly reduced density: not full-blown airbells and visible only in clear blue sky. These were about 3mm in diameter on an 8x10 print. I was meticulous (I thought) in ensuring initial agitation etc, but it still happened.

Then I did a few minutes presoak. The problem went away never to return. FWIW, the film was Neopan400 and the developers were various Sandy King pyrocatechol developers (PMC to begin with then Pyrocat variants).

Why only 120? I don't know, but my results speak for themselves.