Do you Pre-wash your film?

[drewbarb]

The issue of pre-wetting or pre-washing film has come up in several threads recently. This got me thinking. I learned to process film 20 years ago, and never heard of the technique of pre-washing film until I started processing film at a small high-end black and white boutique lab in NYC eight years ago. The guy who founded the lab trains everyone who works there in his methods of processing film, regardless of their experience. His methods include a pre-wash in plain water of all films to be developed in standard developers, except where contra-indicated. The way it was explained to me, pre-washing helps in a variety of ways, including stabilizing the the film at the development temperature, and swelling the emulsion, preparing it for the developer. The idea is that this results in more even and consistent developing, and slightly finer grain.

Regardles of the precise science or voodoo here, I have continued the practice ever since. I now run a small lab offering boutique black and white services to a few other photographers, and I pre-wash all my own film and all the film I run for my clients (except films that will be run in two bath developers like Diafine which specifically indicate not pre-wetting).

So that's what I was taught, and this has been my experience. I'd like to know your thoughts on the practice, and get an idea of if and why people do this or don't do it. Thanks.

(Edit for clarity.)

 

[shadowfox]

His methods include a pre-wash for all films in standard developers, except where contra-indicated. The way it was explained to me, pre-washing helps in a variety of ways, including stabilizing the the film at the development temperature, and swelling the emulsion, preparing it for the developer.

So you pre-wash in the developer to prepare the film for the developer. I'm sorry, I don't get it . Could you elaborate a little on the actual process to help newbies like me?

 

[BillBingham2]

My guess is that you prewash the film in a water bath at the same temperature as you are using throughout the process. Interesting idea, how long do you do it for? My guess is about three minutes, but that is only a guess.

B2 (;->

 

[drewbarb]

So you pre-wash in the developer to prepare the film for the developer. I'm sorry, I don't get it . Could you elaborate a little on the actual process to help newbies like me?

Hey Fox- Sorry- maybe I should have been clearer. Pre-wetting is the practice of soaking the film in plain water before the developer. I use 2 minutes in clean water, same temperature as my dev, same agitation routine. Hopefully this thread will yeild other thoughts on the possible benefits of the practice.

 

[payasam]

Pre-wetting film makes sense, which is why people do it: but if the tank is tapped smartly on the table top once the developer has been poured in, there's little danger of air bubbles remaining.

 

[jan normandale]

Barb, I develop my own. I don't prewash. I read your post to a thread elsewhere here at RFF and saw you mention this part of your process.

Thanks for the idea, I'm going to try it.

 

[nikon_sam]

Drew,

I did it years and years ago (I think it started for me with Ilford films) and then I dropped doing it...
The reasoning back then that I read was "for more even developing and to help prevent pinholes (air bubbles) in film" or something like that...
I think I'll be trying it again...

Thanks,

BTW...I posted two shots in the "Pink Problem" thread for you to gander...

 

[rich815]

I thought I remember somewhere reading that Ilford specifically recommended against it for their films. Something about how it washed away a wetting agent or something that Ilford felt helped in the development process. That said I've started doing it when I use the more specialized developers like Dixactol Lux and Exactol as they are prone to uneven development if the film and canister are a different temp than the developer and if the developer hits the dry film unevenly when being poured into the small tanks. It did help for that. Otherwise with developers like D-76 and Rodinal I sometimes do it when I rememeber but do not recall any benefit or detriment.

 

[oftheherd]

I thought I remember somewhere reading that Ilford specifically recommended against it for their films. Something about how it washed away a wetting agent or something that Ilford felt helped in the development process.
...

I always wondered what Ilford did differently. I noticed back in the 70s that their film dried differently than anyone elses. I just couldn't get uneven drying which was the cause of drying spots or in extreme cases, drying blemishes. A drop of water anywhere on FP4 or HP5 was difussed out in the film and no drying spot. I thought is was neat, and figured it had something to do with the emulsion or base. Maybe it was an additive after all. Whatever, I really liked that about their film.

EDIT: I don't use a prewash. I think I may have tried it a couple of times when I first read about it, didn't see any noticable difference, and decided it was more trouble than it was worth. I know many people swear by the procdure though. As I mentioned in the other thread, I think it had to do both with presumed more even development, and not needing stop bath. Some people think that is too much of a shock to their film.

 

[Doug]

Some films have an anti-halation dye that dissolves out into the developer, staining the developer. If you reuse developer, then you might prefer it not be stained. A pre-wash will dissolve the anti-halation dye to protect the developer. One reason for pre-wash anyway. When I've done it I've also added just a drop of Photo-Flo wetting agent to help avoid air bubbles.

One problem, theoretical, is that after the pre-wash the water now present in the emulsion may slow the developer in reaching where it needs to work, and dilutes it there if only at the beginning. It's this very effect which makes the pre-wash a bad idea with Diafine, which relies on full-strength Part A soaking into the emulsion.

 

[topoxforddoc]

I don't bother and never have. With B/W everything is pretty much at room temp anyway before you start.

Charlie

 

[.JL.]

I don't pre-wet my film, and will probably never try it unless I run into uneven development problems. Fairly consistent results so far, and no problems at all.

 

[sjt]

I have been prewashing films for about 10 years. I pour in pre wash, agitate 10 inversions, tap tank on table to release bubbles. I repeat with the film, and I cut development by 20% to compensate for the dev being able to take quicker due to the emulsion being wet.

The reason I heard for it that convinced me to do it was that the prewash makes the film wet and when the developer is poured in it can take to the film more evenly, thus helping even development. I think the example was illustrated by pouring water over a piece of dry film and the water ran in different directions, wetting the film unevenely where the water ran. If this is dev on a dry film, then this may encourage uneven development where the dev ran first. With a prewash, everything is nice and wet and this is avoided.

Its not much of an effort to prewash, and I haven't had uneven development (well only when I put 7 35mm films in one huge tank and got streaking from the sprocket holes but that's my own stupid fault - I now limit the films in one tank to 3). I usually put the prewash in then mix the dev, measure its temp and then calculate the dev time while the film is soaking in the prewash.

Hope this is useful

 

[rich815]

Ok, we now have in this thread two completely opposite statements:

"One problem, theoretical, is that after the pre-wash the water now present in the emulsion may slow the developer in reaching where it needs to work"

and

"I cut development by 20% to compensate for the dev being able to take quicker due to the emulsion being wet."

So, which is it?

 

[nikon_sam]

I thought I remember somewhere reading that Ilford specifically recommended against it for their films. Something about how it washed away a wetting agent or something that Ilford felt helped in the development process. That said I've started doing it when I use the more specialized developers like Dixactol Lux and Exactol as they are prone to uneven development if the film and canister are a different temp than the developer and if the developer hits the dry film unevenly when being poured into the small tanks. It did help for that. Otherwise with developers like D-76 and Rodinal I sometimes do it when I rememeber but do not recall any benefit or detriment.

Rich,

I honestly don't remember if it was Ilford film or another one...but it was something I read at about the same time I started using Ilford...that was over 20 years ago SO just do the math...(20 years divided by memory loss times pi...) :bang:

 

[nikon_sam]

Ok, we now have in this thread two completely opposite statements:

"One problem, theoretical, is that after the pre-wash the water now present in the emulsion may slow the developer in reaching where it needs to work"

and

"I cut development by 20% to compensate for the dev being able to take quicker due to the emulsion being wet."

So, which is it?

They both could be correct depending on developer being used and the dilution of the developer...just a quick thought and I had to get rid of it...

 

[Never Satisfied]

Hi, I've been prewashing for atleast the last 1o years and have had no problems at all. I prewash for 5 mins and then develope at the normal time with no adjustment becasue of the prewash.

I started this practice when I got uneven development in some rolls of the original Ilford SFX 200. The Ilford rep rcommended it, it worked and I've continued the practice for all films, even for films I have processed on a commercial scale for other labs.

Cheers Andrew.

 

[Pablito]

Having done it both ways, I simply follow the recommendations of film and/or developer manufacturer. Sprint Systems film developer works better, more evenly, with a presoak, which they recommend.

 

[sepiareverb]

Kodak tech support has gone back and forth on this- sometimes saying you should, sometimes you shouldn't. I don't bother unless I'm getting into a short development time- less than 6 minutes I will prewet just to be safe, but like Alex I've never seen any difference in my own or students films. I do prewet sheet films- but more for the ease of handling and to prevent them sticking together in the developer should I not get them fully under before the next sheet goes in- any fussing with partially wet films takes place in the water, so I can concentrate on agitation cycles during developing.

Consider the effect of uneven development on a sheet of paper- very hard to see the difference of even 15 seconds difference of immersion after a 2 minute developing time- with film we have usually a much longer development to even out the small difference in immersion time.

 

[John Robertson]

Pre-wetting film makes sense, which is why people do it: but if the tank is tapped smartly on the table top once the developer has been poured in, there's little danger of air bubbles remaining.

I do both, probably a "belt and braces"thing!! Most E6 processes recommend a pre soak to bring everything up to temp.:angel: