I am not aware of pre-wetting being a "known cause of problems". I didn't presoak for quite a long time, now I do, but I've had no problems with uneven development either with or without presoaking.
Both methods work.
Most uneveness problems I've seen are due to agitation or insufficient amounts of developer in the tank.
Originally Posted by Photo Engineer
Your agitation doesn't seem vigorous enough to distribute the chemistry. Also, did you reuse the same developer, or are you using a one-shot developer? If you reused the same developer in that small amount, then it could have become exhausted by the third roll.
I used to develop (dearly departed and hallowed) Techpan following the Kodak directions. Get the film on the reel, and then drop it into the developer and give it a vigorous up-and-down shake, like mixing a martini. Never had a problem.
As for pre-rinse, use what works. The Ilford instructions say no, Kodak says yes for tray processing. Test it and find out for yourself.
Whatever you want.
Originally Posted by bdial
I have seen it, read about it and had it explained, but please keep doing it. It isn't neccessary in any way, and it MAY cause you problems, but if you want to have an extra step in your process and it may cause problems, please continue as you go, but don't complain when rou run into problems.
There are reasons why most of the professionals in teh world stopped using pre-wetting in the 1930's.
You may use pre-wetting for years without problems, but suddenly you change some minor thing in your workflow, film, developer, temperature, time etc. and you ruin your precious film with a pre-wetting procedure that ISN'T NECESSARY! Please go on and do that if you want, but WHY?
Because you want to introduce another moment in your workflow that may destroy your precious negatives, or because you want to do as others that say that is ok?
It's very OK WITHOUT pre-wetting. Why bother?
I would be very interested in your POV after you read the thread that contains the prewet testing and also the original thread that spawned it. After reading individual comments you will be in a better position to understand the entire continuum of thought on this matter. As it is, after about 60 years of experience in this field most of it as a professional, I have never heard of a professional comment against a prewet. I have heard a difference of opinion expressed and also have Kodak and Jobo documents that recommend a prewet.
But, use what works for you.
Whoa, my initial question seems to have spawned quite a discussion.
Anyways, I started pre-soaking my films quite recently as I didn't like the magenta cast in TMAX negatives, and the pre-soak seems to take care of it. Also I like the thought of beginning with a perfect temperature, both for the film and the developer (and since Tetenal C41 recommends using pre-soak to get an even temperature I thought what the heck...). Maybe I'll stop using pre-soak once I've tried a more vigorous agitation scheme, but I'm trying to change only one variable at the time.
However, it seems to be more important to use a bit more developer and also using additional spirals to make sure that the film is all the way down on the bottom. And perhaps use a more vigorous agitation scheme.
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The magenta cast will be washed out in the final wash. Some remaining color will not be any problem where you scan or wet-print your images.
Besides that, your developer will get a beautiful color if you don't pre-wash. Try developing a TMAX and a Shanghai GP3 in the same developer. You your developer will get a fantastic color. I doesn't hamper the developer or any subsequent films developed in it in any way.
Bromide drag is caused by insufficient agitaion. The other uneven development marks may also come from unsufficient agitation, but pre-wetting increases the need for initial agitaion. My experiments with two-bath developers indicates this. When using a Diafine clone the first bath is to be agitated like normal B6W development, but the second bath, where the emulson is wetted with developer requires CONSTANT agitation to avoid uneven development marks just like you got. This is also described in many books written from 1930 and up til 2010.
Knowing that, why introduce a practice that MAY cause problems. I am not saying thet it will cause problems, but it may.
I like to keep things as simple as possible and in this case it means drop the pre-wash.
BTW, reading the Tetenal instructons, it says pre-heat. That is not pre-wash. It is just placing the tank with the film in the warm water bath for some minutes before you start processing. Using a steeel tank, a few minutes is required. Using a plastic tank, a longer time is required to get it up to the correct temp.
Seems to me that Tronds has a point, if pre-wetting takes care of any magenta cast, so will a thorough final rinse, since both are clean water......
This discussion about an ancient technique is funny, AFAIK it was rendered obsolete by modern film technology in the 1920's as far as I have been able to ascertain. Kodak STOPPED recommending it, and I have translated work here from the 1920's that states it is not necessary.........
There is one side to this discussion that is over-looked IMHO: in what context are we discussing this, what exact development technique?
There has been a resurgence of this pre-wetting technique in an environ ment where this is risky: diluted developers and long dev. times combined with stand or semi-stand development.
First: bromide streaks invariably stems from lack of agitation. There is NO way around that, teach yourself how to agitate properly, and teach yourself what is proper according to the film/developer/dilution you choose to use. Many people dont understand what bromide streaking IS and what causes it, and I think the name is a bit misleading.
Seems to me that some thinks bromide streaking occurs because there is too much bromide in the developer, and suggest taking KBr out, when exactly the opposite is the case! Adding KBr insures a base level concentration of Br in solution - so that the miniscule Br released from the film emulsion does not disturb the rest of the film. (in that context used or old developer should cause less bromide streaking.....)
Pre-wetting is especially risky when one deals with diluted developers, since dilution reduces alkalinity, and any detergent (alkali!) is a help to wetting the entire surface..... Especially the effect of this can be witnessed in countless discussions on other forums dealing with homebrew developers, especially Caffenol.
Combining low-concentration recipes of Caffenol with extremely long development times, semi-stand development AND pre-wetting has caused a flurry of reports of stained & streaking negatives, and several workers have stopped using the technique probably in despoeration....
As to Kodak references to pre-wetting : it is a well known fact that the germans always had better engineers than Kodak....... and in the standard works on photo technology from the 1930's onwards (my tome is from 1955) this is mentioned and NOT recommended. It is dismissed as outdated.
However this is also a question of context: since much of Kodak's work from the 1940's onwards was directed toward the large photofinishing plants and building an empire that locked out amateurs and independent workers from the photo finishing business:
Their big machines, running film continously, pretty much takes care of all what I has said aginst pre-wetting.
So if you have a million dollar, continous running process on hand, pre-wetting can probably be a boon, I don't know, I have a few tanks and a kitchen work bench.
I think you mix up some effects here. If you use a two bath process as the one you described here the first bath's job is to soak the emulsion with developer, but barely any development takes place at this stage. That first bath basically works to completion (emulsion saturated with dev), therefore you run little risk from reduced agitation. The second bath is where the actual development takes place, and if you don't agitate, internal streams in the dev liquid will do it for you (poorly and unevenly), and you'll get uneven development. Prewetting may or may not have an adversarial effect on the first step,it probably depends on the pH of the water you prewet with and how much of that water remains in the tank, but your description has little to do with it.
Originally Posted by Tronds
One comment to the thread starter: Foma film uses older type emulsions compared to T-Max and contains more silver. There is a good chance that Foma simply needs more developer than T-Max. A good way for checking whether that's your problem is looking whether films with less exposure (i.e. less silver halide converted to silver) show less of that effect.
Trying to be the best of whatever I am, even if what I am is no good.
i never heard that it was an outmoded process ..
and even into the 1980s was recommended by both instructors and kodak to do a pre-developer water bath.
when xtol arrived that was the first time i remember being told not to use a water bath to pre-wet ...
that and when i worked for someone who had me doing her deep tank-stuff ...
she didn't use stop either and had a friend with blue hair named muffy,
so naturally i thought she was kind of a punk, and didn't ask many questions ...
I think you mix up somethng here.
Originally Posted by Rudeofus
Pre-wetting is NEVER used with two-bath developers. If you pre-wet a film before pouring in the first bath, the film is already saturated by water, and will not soak up enough developer and ypu may end up with a almost blank film.
The effect of a saturated emulsion is waht causes problems with pre-wetting and a one-step developer.
The emulsion is filled with water and if the agitation is insufficient, the water isn't displaced by developer evenly across the film and uneven development is the result.
In a continous process there is enough agitaton so pre-wetting can be used, but I can't say I remember that it was used at the photo finishing lab I worked for many years ago. It isn't neded and using pre-wetting is just another extra step requiring more time through the machine and more floorspace.
BTW. A 100% correctly made two-step developer does NO development the first bath. There are several ways to control this, mainly pH and restrainers of some kind. Even sugar may be used to restrain development in the first bath.
My PC version is close to that. A part of the film leader placed in the first bath in plain daylight will get slightly grey in 5 minutes. This is accomplished by adjusting the pH to 7.0 and adding some restrainers. Using 4+4 minutes results in a perfectly developed film, IF continous agitation is used for the second bath.