Ilfostop Working Solution - how long do you keep it going?
For some unknown reason, I follow blindly Ilfords recommendations and tend not to use my ilfostop for not much more then a week or two before discarding.
After a discussion the other night, it dawned on me that this is rather wasteful.
What I want to know is how long do people use their Ilfostop working solution for? Do you only discard it when the colour changes? Or, do you get rid of it, if still orange, but after a set time period? I am curious to know
I personally find indicator stop bath a waste of money. The idea was to make the SB appear black when exhausted under the usual amber safelight to warn people during a long printing session. In use SB picks up various bits or crud like paper fibers and bits of emulsion so its not a good idea to save it. Saving used stop bath just makes for one more bottle in the darkroom.
I use either water, a 3% solution of acetic acid or a 1% solution of citric acid. The citric acid has the advantage of being odorless.
Last edited by Gerald C Koch; 04-24-2013 at 12:06 AM. Click to view previous post history.
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I pour it back in the bottle (Kodak ISB). It usually turns brown from age before it ever gets nasty. I continue to use the acetic acid chemistry because that's what darkrooms are supposed to smell like.
Ifostop is a low-odor citric-acid stop bath. Citric acid does not keep nearly as well as an acetic-acid stop since it is an organic compound and prone to bacterial/fungal growth. I mix my citric-acid stop at half-strength and use it one-session. I've stored some for a while, but it quickly grew sludge.
Acetic-acid stop baths, on the other hand, can last for a very long time(e.g., Kodak Indicator Stop). If you are worried about particulates, you can always filter.
Keep in mind that you should not let the indicator in the indicator stop turn completely from orange/yellow to blue/purple. Toss the stop at the first sign of color change, which is usually a muddy grey-yellow. This is the point where the pH starts to be adversely affected and the stop is no longer really effective.
Thanks for your replies. I should probably dilute vinegar, but ilfostop has become part of the process- its nearly habit to use it.
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Why would you risk staining your prints and wasting expensive paper (not to mention patience!) for the sake of a few pence in chemicals? It doesn't make sense to me. Ilford knows the capacity of its chemicals; that's why it recommends replacing after a certain amount of use. Think about what it does - it neutralises the developing agents that only work in alkaline solutions and thus stops them from reacting with the fixer and staining your prints. Excess developer accumulates in the stop bath and neutralises the acid, making it alkaline and thus useless for its stated purpose and you might as well not bother at all. Most modern papers, especially RC, are fairly resilient and you might get away with it, but try some of the classic, fibre-based, graded papers and you're asking for stains. If you want to save pennies, of course you can use vinegar but you'll still have to replace it regularly.
Been there, done that in a college darkroom where the stop bath was usually so tired it smelt of ammonia!
Last edited by kevs; 04-26-2013 at 02:25 AM. Click to view previous post history.
In my college darkroom, the smell and taste of powdered D-76 in the air from idiots pouring it from the can into the bottle of water and shaking it up--overpowered the acid fixer. A working solution of Kodak ISB doesn't smell like anything.
Originally Posted by kevs
I use Kodak Indicator Stop Bath until it changes color. I would use the Ilford product the same way.
I only re-use stop bath (when printing) if I am printing two days in a row, and I have lots of remaining capacity after the first day.
For film, I use it at half strength. If I am doing two or more rounds of development on a single day I'll re-use it during that day. Otherwise I use it one-shot.
I also use Ilfostop while printing (because of the odor) and Kodak Indicator Stop for film (because of the economy).
“Photography is a complex and fluid medium, and its many factors are not applied in simple sequence. Rather, the process may be likened to the art of the juggler in keeping many balls in the air at one time!”
Ansel Adams, from the introduction to The Negative - The New Ansel Adams Photography Series / Book 2