How do YOU pre-soak?

MattKing · 2025-04-22T17:07:31-0400

BobUK said:
Partial quote..

I don't understand that bit myself, so hopefully I am on the correct course.

At the end of dev, fix and wash, I transfer the loaded film spiral to a separate bowl of fresh water with a tiny amount of wetting agent. My wetting agent does not go anywhere near the tank. Then the emptied spiral is given a thorough good wash.

If you are adding wetting agent to the tank for the final rinse is, there a possibility that the tank is assumed to be clean after all the rinsing,and not being thoroughly washed clean of the wetting agent?
So you end up with the developer wetting agent, plus the residue wetting agent from the previous final rinse.

I have been very lucky and never had a frothy brew.

The OP is referencing the trace amounts of surfactant that are added by the manufacturer to certain film emulsions in order to ensure even wetting at the time of development - most likely to avoid problems with some commercial dip and dunk lines.

pbromaghin · 2025-04-22T18:29:36-0400

Doremus Scudder said:
It seems you want to know how you should pre-soak, not how we do it. So might I be so bold:

You need to remove the surfactants from the film to both prevent accumulation in your replenished developer and prevent uneven development. Not fully removing enough of the surfactants will cause uneven development. Really, you are after a pre-wash, not a pre-soak (the terms are not interchangeable).

So, you need to proceed like your were washing film. A fill-and-dump regime if you're using tanks or a running-water or multi-tray regime if you're using sheet fill seems necessary to me. A longer time than what is needed to saturate the emulsion would also seem in order.

I'd start with a five-minute soak with changes of water and gentle, continuous agitation. Tap water is just fine; if you can wash your film with it, you can pre-soak in it as well. Use the same temperature as the rest of your process.

If you still have foaming problems with your developer or uneven development problems after that, then you'll need to extend the pre-wash.

Best,

Doremus

Hmmmm. Very perceptive. I hadn't thought of pre-soak and pre-wash as 2 different processes, but that an assembly of APUG wisdom would give clues on how to go about it.

I wonder, would it be worthwhile to include Harmon Washaid, normally used on papers?

pbromaghin · 2025-04-22T19:54:13-0400

BobUK said:
Partial quote..

I don't understand that bit myself, so hopefully I am on the correct course.

Any debate concerning the benefit or lack thereof with presoak usually ends up going round and round, with arguments between minds that have been firmly made up and may end in insults with one of the participants melting down and leaving after having the mods delete all record of his ever having been here.

pbromaghin · 2025-04-22T21:13:38-0400

pbromaghin said:
I wonder, would it be worthwhile to include Harmon Washaid, normally used on papers?

I just realized how dumb this would be. Washing off one substance and replacing it with another?

Photosandpotatoes · 2025-04-22T22:40:39-0400

Illuminating thread! I’ve been wondering how others do this.

Doremus Scudder said:
It seems you want to know how you should pre-soak, not how we do it. So might I be so bold:

You need to remove the surfactants from the film to both prevent accumulation in your replenished developer and prevent uneven development. Not fully removing enough of the surfactants will cause uneven development. Really, you are after a pre-wash, not a pre-soak (the terms are not interchangeable).

So, you need to proceed like your were washing film. A fill-and-dump regime if you're using tanks or a running-water or multi-tray regime if you're using sheet fill seems necessary to me. A longer time than what is needed to saturate the emulsion would also seem in order.

I'd start with a five-minute soak with changes of water and gentle, continuous agitation. Tap water is just fine; if you can wash your film with it, you can pre-soak in it as well. Use the same temperature as the rest of your process.

If you still have foaming problems with your developer or uneven development problems after that, then you'll need to extend the pre-wash.

Best,

Doremus

What’s the difference between presoak and pre wash? When would you do one vs the other?

Craig · 2025-04-22T23:50:44-0400

pbromaghin said:
I wonder, would it be worthwhile to include Harmon Washaid, normally used on papers?

No, because that is intended to remove the residual fixer compounds. At the stage of processing you are contemplating, there isn't anything for it to work on.

Thinking of the foaming, are you making sure the tanks are scrupulously clean so there is no wetting agent carry over, and are you also observing the capacity? D76 can only be replenished a finite amount and there is a hard limit to the amount of film that can go through a replentished solution before it must be dumped.

Vaughn · 2025-04-23T01:19:11-0400

Photosandpotatoes said:
Illuminating thread! I’ve been wondering how others do this.

What’s the difference between presoak and pre wash? When would you do one vs the other?

I'm trying to previsualize a presoak and/or a prewash. Prior to using developer (the 'pre' part) I suppose one would soak the emulsion just to get it swelled, wet, and ready. And one would wash the emulsion to remove any water soluable additives to the emulsion. It seems it would be difficult not to have a soak also be a wash.

RalphLambrecht · 2025-04-23T01:39:14-0400

General answer: at processing temp for min 5min with intermittent agitation every 30s

pbromaghin · 2025-04-23T09:57:26-0400

Craig said:
No, because that is intended to remove the residual fixer compounds. At the stage of processing you are contemplating, there isn't anything for it to work on.

Thinking of the foaming, are you making sure the tanks are scrupulously clean so there is no wetting agent carry over, and are you also observing the capacity? D76 can only be replenished a finite amount and there is a hard limit to the amount of film that can go through a replentished solution before it must be dumped.

It’s only halfway through the replenishment routine and none of my tanks or reels have been touched by photoflo in over 5 years. So we’re safe there.

runswithsizzers · 2025-04-23T10:28:34-0400

I've been pre-washing evey b&w negative film with temperature-adjusted tap water for 60 seconds with constant agitation. However, I have been experiencing some uneven development with 120 film, only, so I should probably try skipping the pre-wash to see if that helps. Either that, or doubling my pre-wash time.

Agitation, surge, and uneven development?

I have been noticing pale edges on my darkroom prints from b&w 120 negatives. My assumption is, this may be caused by "surge" -- that is, an increase in development at the edge of the reels due to turbulence when agitating. I am using stainless steel tanks and reels, sometimes one 120 reel in a...

www.photrio.com

BobUK said:
I have been very lucky and never had a frothy brew.

I would consider myself very unlucky if I was not able to enjoy a frothy brew at least once a week. And unless things have changed since I was last there, you have some very good frothy brews on your side of the Atlantic. ;-)

How do YOU pre-soak?

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