soaking in water before processing?

[Matt5791]

I have heard of people soaking film in 20 deg water prior to processing to ensure that the film and tank are at 20 degrees.

I have tried this on a couple of previous processing sessions with no adverse effects, although when I pour the water away it is a dark, mabey purple, colour.

Is it OK to pre soak and does it change anything?

I have read Ansel Adams and he has talked about presoaking (I think) - is this the same thing?

Is what I am doing OK?

What about the colour fo the water - was I pouring the film emulsion down the drain!?

Thanks for any advice,
Matt

[Dave Miller]

It's the proceedure I follow; the coloured water is, I think, the antihalation dye coming out of the film, and is not detrimental. The important ting must be the state of your film after you have developed it.

[fhovie]

Presoaking does several things. It tempers the tank and film so that your developer temperature will stay correct. It washes off the anti-halation layer on the back of the film which likely doesn't effect the development process at all. It also swells the emulsion a little as the water soaks in. When you replace the water with the developer, the developer graduly replaces the water in the emulsion (St. Ansel says it takes 20 seconds) which allows for a more even development. This way all the surface of the film gets a slightly buffered exposure to the developer as it unevenly enters the tank and sloshes around until full. I always pre-soak. It is likely less important with smaller formats.

[Matt5791]

Thanks for the replies - very interesting.

St. Ansel - I like that!

Matt

[mono]

Presoaking does several things. It tempers the tank and film so that your developer temperature will stay correct. It washes off the anti-halation layer on the back of the film which likely doesn't effect the development process at all. It also swells the emulsion a little as the water soaks in. When you replace the water with the developer, the developer graduly replaces the water in the emulsion (St. Ansel says it takes 20 seconds) which allows for a more even development. This way all the surface of the film gets a slightly buffered exposure to the developer as it unevenly enters the tank and sloshes around until full. I always pre-soak. It is likely less important with smaller formats.

I always pre-soak, too, for the same reasons mentioned above!

[Matt5791]

Just thinking - what is a good pre soak time? 2 minutes or something?

Thanks

Matt

[Tom Hoskinson]

My standard pre-soak time is 5 minutes (I use deionized water - I have a Millipore filtration chain in my Lab). I use the 5 minute pre-soak with both rollfilm and sheet film.

[Matt5791]

Thanks!

Matt

[mono]

all formats, 2 min, 20 degrees, normal water, continuous agitation: up and down and turning around and then I use my tested (densitometer) film development time

[pentaxuser]

I have heard of people soaking film in 20 deg water prior to processing to ensure that the film and tank are at 20 degrees.

I have tried this on a couple of previous processing sessions with no adverse effects, although when I pour the water away it is a dark, mabey purple, colour.

Is it OK to pre soak and does it change anything?

I have read Ansel Adams and he has talked about presoaking (I think) - is this the same thing?

Is what I am doing OK?

What about the colour fo the water - was I pouring the film emulsion down the drain!?

Thanks for any advice,
Matt

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