Rolf-Werner
Hi,
Two quick questions, the first out of pure curiosity. Since I’ve been using Adotol-Konstant, I’ve noticed that it leaves a yellowish-white powder behind when it dries (splashes). What is that? I used to always use liquid concentrates, mostly Eukobrom, and that didn’t happen then; I’d only ever seen it with the fixer.
Second question: Today it seemed to me as though the batch of Stopper I’d prepared had gone off. It smelled like a vase of flowers where the water had been left in for too long. Could that be the case, or is my nose playing tricks on me? I had a sniff of the fixer; it smells slightly sulphurous, as usual, but not rotten. The smell had gone for a while, but after a bit it kept coming back up from the bowl, even when I poured it back into the bottle. Only the residue in the bowl didn’t smell. Is that even possible? The colour was fine, by the way – yellow, not off.
Perhaps you’ve had experience with this.
Regards,
Rolf
KlausWehner
Every developer consists of various substances dissolved in water.
When the water evaporates, these substances remain behind.
This also applies to Eukobrom.
There are various chemicals used as stop baths: acetic acid, disulphite, citric acid.
Citric acid, in particular, does not keep well and tends to go mouldy.
Perhaps you have a stop bath containing citric acid? If so, it should be replaced regularly.
Best regards,
Klaus
Rolf-Werner
Yes, Klaus, citric acid. It’s probably gone mouldy. I’ll just use a different container...
Thanks for the tips!
Rolf
KlausWehner
Replace the citric acid-based stop bath as soon as possible.
In the long term, I would use a different stop bath.
Best regards,
Klaus
PeterK
Hello,
A citric acid-based stop bath is so cheap that it isn’t worth keeping it as a solution for any length of time. For the positive process, simply add 1 tablespoon of crystallised citric acid to a litre of water, give it a stir, and you’re done!
You can get citric acid in any decent chemist’s or (perhaps slightly more expensive) pharmacy.
For the positive process, there’s no need to buy a branded product. If you complete the development fully (after the recommended time) – which you should always do – the stop bath simply prevents any developer from carrying over into the fixing bath.
When developing negatives, I don’t use a stop bath at all, but simply rinse twice after development. Of course, the film continues to develop slightly in the water, but if I stick strictly to the rinsing time (in my case: pour in, tilt four times, pour out), I can simply factor this difference into the development time.
Dongrappo
PeterK wrote
: Hello,
A stop bath based on citric acid is so cheap that it isn’t worth keeping it as a solution for any length of time. For positive processing, simply add 1 tablespoon of crystallised citric acid to a litre of water, give it a stir, and you’re done!
What do you mean by ‘long-term storage’? And what is the yield with citric acid?
I also use citric acid and think it’s brilliant. I haven’t had any problems so far and only use it for a maximum of 3 days, provided these aren’t too far apart, so a maximum of two weeks’ storage. Of course, the long-term effect and archival stability are always a bit of a question mark. Although I’ll only be using PE paper for the foreseeable future.
When developing negatives, I just rinse with water and have never had any problems.
KlausWehner
The main purpose of a stop bath is to protect the subsequent fixing bath.
The developer is strongly alkaline, whilst the fixing bath is usually slightly acidic.
The stop bath neutralises the alkaline residues from the developer, thereby preventing the pH of the fixing bath from gradually changing due to the introduction of alkali.
Whether or not to use a stop bath depends on the specifics of the processing.
Personally, I fix using the ‘two-bath method’. The second fixing bath is always (relatively) fresh.
In the negative process, I only use the fixing bath once.
Under such circumstances, a single rinse after development would indeed suffice.
If only one fixing bath is used and this is employed over a longer period, I would certainly not do without a stop bath.
Particularly in the positive process, it is hardly noticeable at first if the fixing bath is no longer fully effective.
The consequences go unnoticed initially and often only become apparent weeks or months later.
Reliable fixing is extremely important.
A stop bath may protect the fixing bath from premature loss of activity.
It is advisable to test the fixing bath regularly (‘clarification time’).
A ‘two-bath fixing’ process is recommended (in which case a stop bath may be dispensable).
Best regards
Klaus
