Why Presoak?

[DanK]

I dip and dunk sheet film and always pre-wet/pre-soak in plain water prior to development - but only for 60 seconds or so....

I was taught the pre-soak softens the anti-halation layer and/or super-coating allowing a more even development...so it has become ritual...

Although, I doubt I'd see a difference....I don't pre-wet/pre-soak roll films...

Dan

[coops]

I had some uneven development also with the Jobo, but sinse I started pre-soaking, no problems

[Gary L. Quay]

I've done it both ways, but I've never seen a difference.

I have heard, however, that when you use a pre-soak, allow 30 seconds extra development time for the developer to reach the emulsion.

--Gary

[Peter De Smidt]

So,

The reasons to pre-soak:
1) bring the emulsion up to temp.
2) get rid of air bubbles.
3) make handling easier, such as with tray processing.
4) lengthen the development time.
5) get dye out of emulsion (although I don't know why you'd want to do it.)
6) increase evenness of development with some films and processes.

The reasons not to do it:
1) It's an extra step.
2) It might lead to less even developing with some films/processes.
3) It lengthens development time.

Btw., all films/develop combos don't respond in the same way to a pre-rinse. I've heard of it actually increasing contrast, for example. The length of time is very important. Do it the same way each time. Jobo found that times much shorter than 5 minutes lead to variable results. The best way to tell if it helps for you is to try it in a controlled way. When I processed sheet film in trays, I used one. Since moving to a Jobo with and expert drum, I have not, at least with BW.

[jim kitchen]

Folks,

I pre-soak for six minutes, no more no less, whether I use Ilford films, Kodak films and, or a rotational device with both films, and I would surely tell you in heart-beat if pre-soaking affected my development process or not...

I have pre-soaked my film for more than thirty years, and I have yet to see any detriment to this issue. If Ilford, for example, says that you should not, and if you follow their recommendation, complete with a few staunch Ilford supporters emphatically stating that fact, then do it. I must tell you that pre-soaking my film is an important step within my film development process, and I would not recommend removing this step, period. My previous film development times that I published for TMY-2 did not state this fact, because I forgot to include that comment.

That said, it is your choice, your process, and your results that you should be concerned with, going forward. Experiment, and you will see whether it is an important step or not.

Just my two pennies...

jim k

[davemiller]

I pre-soak for five minutes as part of my temperature stabilisation process for both roll and sheet film.

[Brian Ellis]

Depends on how much you enjoy standing in a darkroom inhaling chemical fumes. If that's something you enjoy then presoak. If you don't enjoy that then don't presoak.

I've done it both ways and never noticed any difference at all. My impression is that presoaking used to be standard procedure with the old "thick emulsion" films because with those films it promoted even development (not sure where I read that or how true it is, it's just something I read somewhere some time). With today's films I don't think it serves any purpose and in some cases (e.g. Ilford films) may actually create problems though I presoaked HP5+ for a while when I was using pyro and never saw any problems. Basically I think it's a non-issue, do whatever you want to do, it isn't going to matter either way except in terms of how much time you spend in the darkroom.

[bob carnie]

One of the reasons for presoak is to swell the emulsion and make it able to accept the developer faster.
I use distilled water for my developers , because I believe the lack of minerals allow less resistance for the developer to get to the film.

I gleaned this from reading and re reading Gordon Hutchings writings.

I use rotary for the last 15 years and only presoak Pyro process, for D76 and others I do not presoak.

As well , even though I use rotary, I manually agitate for the first 20 seconds of any run. From a nasty bout of road ruts , that almost drove me insane and stopped all customer film production.

[wclavey]

I never used pre-soaking for 20+ years of MF film development until I started using Arista EDU branded FOMA film. I had terrible problems with air bells and used the pre-soak as a way to eliminate them. Then, when I started shooting 4x5, I noticed that if I included the pre-soak it eliminated the streaking problems I sometimes had in the sky (as someone described above). I use a Jobo tank and a Uniroller for all my film now, all formats, and I pre-soak for 4 minutes in 700ml of water with 7 drops of photoflow.

[Paul Metcalf]

Here's another take on presoaking for those that use Jobo print drums for 8x10 or larger film that spans one or more of the small ridges in the drum. There have been other posts in the past that have mentioned that when doing this they get lines on the film when using pyro/staining developers but the lines only show up when printed. Hence the belief that the ridges in the tank cause this. Speculation is that the ridges cause some sort of additional stress or such, maybe even a difference in the speed of the chemical flow over the bumps, in which either case effects the hardening of the film in that area. And from what I've been able to gather it seems as though those that have had this problem do not presoak.

MY speculation is that the film is in more direct contact with the tube at these ridges such that the film temp is different due to difference in heat transfer for some amount of the initial development, hence the different hardening and lines in the prints. I've never had the lines in my prints, and I presoak for 5 minutes, so I'm quessing that the overall film, even along the ridges, is at the same temp and thus recieves equal development and hardening. YMMV, and I could be full of it, which is ok, because I don't get lines in any case!

Westley - I would be concerned about chemical contamination with the photoflo prior to the developer unless it was rinsed well, but if you haven't had any problems, I guess it's not an issue.