Discussion in 'Talk About Developing Film' started by Ian-Barber, Aug 25, 2016.
How effective is using water in place of say Ilford Stop Bath
If you're using an alkaline developer (most are, but not all) then an acid stop bath will stop the development in its tracks. Well, pretty much. And it will keep the fixer acid (assuming its an acid fixer, most are). So the arguments for a stop bath are rapid termination of development, to aid consistency, and longer life for the fixer.
On the other hand, in the time it takes to pour in the wash, shake it about and pour it out, replacing it with fixer, not a lot will have happened. Unless your developing times are very short, the extra time will be negligible.
Viewed this way, the only purpose of the stop bath is to prevent adding developer to the fixer that you'll be reusing.
I'd say that in practice, it makes very little actual difference. There could be a counter argument to using an acid stop between alkaline developer and acid fixer in that by using water you're reducing the effect of a rapid change in pH. The Film Developing Cookbook (well worth reading cover to cover) has comments on this when looking at working in a completely acid or alkaline environment.
I haven't used an acid stop bath for film for many years. Could be due to the type of developers and fix I use; could be a few of the films I use. For example, a water stop bath is highly recommended for any type of pyro developer--the only exception to this that I'm aware of is ABC Pyro where Michael A. Smith says that either is fine. I use a lot of EFKE 25 film. The manufacturer recommends a water stop.
The main issue with the transfer from developer to an acid stop is gas bubbles that may form due to the extreme change in environment--alkaline to acid; depending, of course, on the developer used. You don't want this because it causes holes in your emulsion! Don't ask me how I know that?
Without actually checking, Im not sure what Ilford Ilfostop is but im guessing then that using it is more recommended than using plain water
From memory, it's a citric acid (odourless) acid stop bath.
I normally use Ilfostop, other than for the Efke IR film where it causes pinholes as Alan mentioned. In that case I use two changes of water at the process temperature. That seems to work fine, and most likely washes out the tank sufficiently to preserve the fixer.
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Thanks, I will stick with Ilfostop I think
I use tapwater as a stop bath, same for prints.
If you want to stop, use diluted vinager (2% I think). Very cheap; 1€/L, diluted this way it is not so stinking and it is the same acidic pH as citric acid (well maybe a bit more acidic).
I don't like the smell of vinegar, but prefer an acetic acid stop bath to a citric acid one, for the pragmatic reason that citric acid can go mouldy, and acetic acid doesn't. How many mouldy pickled onions have you seen, compared to mouldy lemons?
If using vinegar, go for white (looks like water) rather than malt (looks like Coca Cola). I suppose (whimsical thought, and I don't recommend it or advise it) that as Coca Cola has the same pH as dilute hydrochloric acid, you could use that.
I generally use Ilford stop bath except with Foma. I use a couple of changes of water. No scientific logic behind this apart from what I have read. I think it was a bloke called Robert Vonk, who said that Fomapan was formulated before stop bath. The sudden change in PH can pop holes in the emulsion. Still get the occasional one of those and I have been known to scratch the odd sheet with rough skin and fat fingers.
I read somewhere that a waterbath stops the developer within 15 seconds and that an all-alkaline-line from developer to fixer (yes I use an alkali fixer) should be best for film and print developing. And so I don´t need an abrupt stop-bath. And it works for me ;-)
Does this in effect keep the film developing for an extra 15 seconds
Development continues but more in the shadows than in the highlights. Diffusion will reduce the amount of developing agents in the emulsion, and the areas of more active development (i.e. the highlights) will exhaust the developer more quickly. It's the reason water bath development works to reduce contrast.
Consistency matters more than anything else in getting predictable results, and if you've effectively factored in the extra development in setting your development time, it's of no real practical consequence. Of course, if your total developing time was only 5 minutes, it would matter more as a proportion of the whole, so the total developing time is also relevant.
I also use alkali fixer but more for paper, it doesn't smell and work very good.
So apart from a cost saving, there is no real advantage then aprt from maybe a slight reduction in contrast
?????? that's probably because I keep the pickled onions submerged in vinegar as against sitting out in the mould-filled 'fresh air' with the lemons.
The number of changes of water that you'd probably make in using a water stop bath (one ?) wouldn't be enough to prevent some alkaline carry over into the fixer, so the fixer's pH would drop (by a very small amount) over time using water. But probably not by a photographically significant amount; and it would become slightly more dilute. The same applies if you're using a stop bath with regard to dilution, and this time you're adding acid rather than alkali.
The main advantage to using a stop bath is the rapid cessation of development for consistency - but as I said above, you can still be consistent with water.
Some developers do contain "stronger" alkalis than others, Rodinal being a prime example. Alkali, like acid, does vary. You might well notice if you spilled dilute hydrochloric acid on your hand, but wouldn't if it were Coca Cola, despite the alkalinity being about the same. I've used a stop bath for years, without problems, and as a Rodinal user, will continue.
I've never had an acetic acid stop bath form mould; the same isn't true of a citric acid one.
Not to be misunderstood with the "15 sec":
I use a water flow for about a minute as water stop.
There is, at least, one more reason...
If using a more alkali developer (as Stephen notes), an abrupt change to an acid environment can cause pinholes due to gas bubbles. You don't want that! A water stop will eliminate this issue. I will say, however, that after many years of developing all formats of film from 35mm to 8x10 I've not had much issue with pinholes; I think it may be emulsion dependent, too! Nowadays, my choice of acid stop or water stop is based more on the developer used--for example, I use a water stop with pyro developers--and/or the film used--I use water stop for EFKE 25 due to it soft and fragile emulsion.
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