Pre-wash of film - good or bad???

[Kevin Crisp]

Traditionally, the justification for a pre-wash was promoting more even development. I never understood how that could be. If I submerge a sheet of film in a tray, the developer contacts all parts of the emulsion plus or minus a fraction of a second difference. That tiny, tiny relative difference in the start time of development is never going to be detectable on the negative. And even if the film is already "wet," then it would still not be completely instantaneous. I've never done it with Kodak or Ilford films and had no issues. The two to three seconds it takes to fill a roll film tank doesn't make the deeper parts of the emulsion noticeably more dense, and that difference is far more than wetting a sheet of film.

Now if the FOMA green dyes are an issue that might be different. And I don't know what 'developer shock' is unless it relates to price.

[Michael R]

Largely agree.

I’m limiting my comments to B&W negatives.

Pre-soaking sheet film is important for tray shuffling if the sheets are added to the solution in relatively quick succession, so that they don’t stick together.

For all other processing techniques in tanks, drums etc. the traditional wisdom is that pre-soaking helps promote more even development where the film is not uniformly wetted (for example pouring solutions into tanks during which there can be splashing of developer onto parts of the film). However this seems to be based on the assumption wet film slows down development - ie that it takes time for the developer to increase in concentration within the water-soaked emulsion, whereas I have found the opposite to be the case - ie development starts faster when the film is pre-soaked, likely due to swell among other things.

Unfortunately it’s yet another one of those potentially contentious topics. Quite a few potential variables including the film, developer, processing, not to mention evaluation of development uniformity (you can’t rely on what users say works or doesn’t work). Lack of evidence, poorly written/ambiguous instructions unlikely to have been based on thorough testing, etc. Some people swear by it. Others don’t. Altitude, phase of the moon, planetary alignment…

Traditionally, the justification for a pre-wash was promoting more even development. I never understood how that could be. If I submerge a sheet of film in a tray, the developer contacts all parts of the emulsion plus or minus a fraction of a second difference. That tiny, tiny relative difference in the start time of development is never going to be detectable on the negative. And even if the film is already "wet," then it would still not be completely instantaneous. I've never done it with Kodak or Ilford films and had no issues. The two to three seconds it takes to fill a roll film tank doesn't make the deeper parts of the emulsion noticeably more dense, and that difference is far more than wetting a sheet of film.

Now if the FOMA green dyes are an issue that might be different. And I don't know what 'developer shock' is unless it relates to price.

[Salmo22]

I presoak Kodak films, and, like Andrew, I never presoaked Ilford films. This methodology has worked well for me.

[Gudmundur Ingolfsson]

Developing 120 film on reels especially on steel reels was disastrous till I took up pre-washing . I pre wet all films also Ilford and see no harm done to Ilford film.

[Tom Monego]

In my early years of large format photography, I never presoaked film and I would occasionally get air bells, what ever you call clear spots on the film. I started prewashing at the suggestion from a prof at college. Since then I have never had clear spots on my film. Early on I mostly used Super XX and TriX Pro. I then switched to TMax 400. I started using large format again this winter, with the cost of TMax films I started to use Ilford HP5+. This film has a lot of dyes that get washed out with the presoak. I definitely think presoaking is the way to go, Kodak or Ilford. I tried Foma100 with 120, but that is another thread.

[jnantz]

some people confuse religion with various aspects of photography. try both and do what you like and don't listen to the static telling you that you are doing it all wrong, there's always people who will say that ..

[Vaughn]

Toss in more variables such as the use of Jobo Expert Drums and their (Jobo's) recommendations, and it is pretty much about being consistent with what works best in one's space and workflow. Hi ho Silver!

[LabRat]

Pre-soak will start the removal process of the AH dye backing layer where it gets better removed during the rest of the process... And it can equalize the thickness of emulsion that dried, got hot/cold, old, swollen etc during shooting/shipping/storage that allows more even development over an entire sheet of roll of film... It worked with many makes/types of film...

I allow 5 minutes pre-soak with a drop per liter of Photo-Flo 200 (diluted 1:2) before all B/W processing and get perfectly even development (without airbells) every time...

An example was when I was supervising intermediate/advanced foto students, where one lady had returned from a whirlwind 12 city US + Euro trip carrying the same batch of 25 rolls of mixed brand/type of 35mm B/W films... She did everything correctly processing the first 4 reel processing run, but the films came out blotchy/uneven density along film, and dried with kinks along with the blotchy areas... I asked if she was air traveling, and she thought it might have been all the X-rays, but I didn't see fogging, just uneven development... Told her to pre-soak film for a few minutes before developer, and all the rest of film came out evenly developed and dried straight!!!

Very dry film seems to harden and not absorb developer like less dry areas, so edge areas could have dried more and give a different density during development... Or bulges can have different overall densities..


I think it's a must for film, especially after air travel, where the film starts to dry unevenly due to the bone dry humidity on airplanes...

Steve K

[rawitz]

Prewash in BW development never is wrong, but the question to expand, keep or even shorten developing time is not clearly answered. Maybe it depends on the film.
But prewash with Colorfilm is another issue. My C-41 process with sheetfilm 8x10 in Jobodrums sometimes resulted in uneven areas, as I found caused by uneven wetting at the start of the color developer (by rotating technic and reduced chemistry).
A 5 min water-prewash solved the problem, but there was a clear color-shift. Modern colorfilms have 3x3 color-layers stacked and the chemistry has to penetrate in an exact order, given by temperature and handling of the process. This is not any more given by prewash.

regards
Rainer

[Mark J]

Amazing stuff. I've never used a pre-wash in 35 years of developing rollfilm ( mostly ) and 35mm, most of this on stainless steel reels. The only film that ever gave me problems was Technical Pan on Paterson plastic reels. Other than this, ZERO problems. This includes air flights eg. coming back from Utah in 1999 with 28 rolls of 120.
Ilford specifically warn against it on all current datasheets : "A pre-rinse is not recommended, as it can lead to uneven processing".
The only other mention I can see in any datasheets, is Kodak saying that it can help in tray-processing of sheet film. I wouldn't argue with this.