How long do you presoak?

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?

I never pre-soak B&W films of any format 35mm to 10x8, if I did like I do with C41 then it would be for 2-3 minutes that allows the tank to come to temperature.

Ian

The object of pre-soaking is twofold. For me, it is mainly to get the emulsion thoroughly saturated so that the sheets of film don't stick together when tray developing. This means submerging each sheet one-at-a-time in the pre-soak at intervals. For me, the sheets will stick together unless the interval is at least 15 seconds. After the last sheet is in the pre-soak, I shuffle through the stack for 2 minutes to make sure that the emulsion is fully saturated. I can imagine that a not-completely-saturated emulsion when put in the developer might exhibit uneven development due to uneven diffusion of the developer.

Which brings us to the second reason for pre-soaking; ensuring even development. In theory, if you get all of the negative into the developer quickly (simultaneously) the developer will diffuse into the emulsion at the same rate and a pre-soak is not necessary. Sometimes, this is not always easy (e.g., pouring time in tall tanks with many rolls, etc.) and a pre-soak seems to slow down the rate of absorption of developer enough to prevent streaks and mottling.

In either case, making sure the emulsion is completely saturated with water is important. I think five minutes is overkill (three works for me just fine), but will certainly ensure complete saturation. Films with thicker, harder emulsions will take up water more slowly, so when in doubt, longer is better.

Someone out there likely has better data on exactly how long it takes for film emulsions to become completely saturated. Maybe they'll chime in.

Best,

Doremus

Five minutes here.
Steve

I generally pre-soak b&w for 1 minute.

For zero seconds.

5 minutes in tap water at processing temperature.

RR

RobC said:

For zero seconds.

Click to expand...

Ditto

But I normally develop prints (8x10) in a tube or as singletons (up to 16x20) in tray - tilt tray lay down paper dry level try for wave submerge run squeegee over any bubbles... Rare to get bubbles always get dust storms instead.

Some of the film emulsions I still use are not prehardened so I process for minimal emulsion damage risk.

2 minutes

I presoak for three minutes. I started doing this when I bought my Jobo CPE-2 and read the manual.

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?

Click to expand...

I'm in the 'no need' camp but if I presoak then a min of 5min to prevent uneven development.

What works for me is two minutes.

Water at same temperature as all other chemicals.

Agitation as per development: 4 gentle inversions in the first 30 seconds followed by a sharp tap on the bottom of the tank to dispel any potential air bells and then one gentle inversion every 30 seconds followed by a sharp tap on the bottom of the tank to dispel any potential air bells.

Bests,

David.
www.dsallen.de

RobC said:

For zero seconds.

Click to expand...

Amen.

I presoak my film for zero seconds.

Never. No reason to unless you tray develop MULTIPLE sheets. Otherwise just slide the sheet in.

Never pour developer through the lid to fill. The bigger the tank, the more problems. Drop leaded reel(s) into a prefilled tank using a lift rod as required.

Many plastic tanks a made so they fill from bottom up and they are fool proof. Stainless, not so.

Zero seconds with Kodak or Ilford. Sixty seconds with Arista/Foma/Adox. These films produce strongly colored rinse water as a result and I often only develop for five minutes due to their rapid contrast buildup in D76. And I've been pouring the developer through the top of my 35/120 tanks for 40 years now, with no uneven development.

Never pre-soak, never have. No need I use SS reels and tanks and a water bath.

RobC said:

For zero seconds.

Click to expand...

Have you tried doubling that time to see if it makes any difference?

Steve

I just shuffle through the sheets in the tray, maybe 30 seconds? Just so they don't stick in the developer.

Steve Roberts said:

Have you tried doubling that time to see if it makes any difference?

Steve

Click to expand...

never tried but next time I will.

Three minutes.

This gives me just enough time to reach the correct level of spiritual one-ness 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.

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 neads 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.

By the time some of you will just finish with pre-soak, I'll be on fixing stage already.
Currently I have three different films for BW which are 3/3 minutes for develop/fix.
Polypan F, Kodak 50D in 135 and Shanghai 100 in 4x5.
Cheers, Ko.

I only pre soak for stand development. usually that is around 3-5 min. depending on my mood and other b.s. is the darkroom.

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?

Click to expand...

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?