Curious incident of obnoxious smell in Thornton Bath B

[snusmumriken]

Today I went to process the third film in my current batch of Thornton's 2-bath developer, mixed 6 weeks ago, and noticed that there was an unpleasant - actually obnoxious - smell coming from Bath B. It was not discoloured beyond a very pale straw colour, consistent with its age and low film count so far. I was impatient, and not too worried about the images on this film, so I pressed ahead anyway, and can see no fault in development of the negatives.

I have since discarded both baths and will mix a new batch. So it's not a problem. I am just curious whether anyone else has ever had this experience, and what could possibly be the cause? I have never encountered this issue with any darkroom chemical before. It smelled a bit like a sourdough culture that has gone off and turned into the wrong ecosystem (if any forum members have that experience). So I wondered about a fungal or bacterial contamination. I mix all chemicals with our tap water, but that is locally UV-treated. I always use the same bottles for the same chemicals, and they don't sit around empty.

 

[koraks]

It smelled a bit like a sourdough culture that has gone off and turned into the wrong ecosystem (if any forum members have that experience).

Yeah, I know what you mean - which is to say, this can be kind of (very) variable as well. The first kind of smell that comes to mind is something like "socks worn on a hot day for two days on end and then left inside a plastic bag for another 3 days". But I can't quite marry that to any smell you would typically get from any darkroom chemistry. If the smell does indeed sort of match that description, my guess would be something bacterial.

 

[snusmumriken]

Yeah, I know what you mean - which is to say, this can be kind of (very) variable as well. The first kind of smell that comes to mind is something like "socks worn on a hot day for two days on end and then left inside a plastic bag for another 3 days". But I can't quite marry that to any smell you would typically get from any darkroom chemistry. If the smell does indeed sort of match that description, my guess would be something bacterial.

I don't know what the pH of that bath would be, but doesn't it seem unexpected that common-or-garden domestic bacteria would thrive in an alkaline solution?

 

[koraks]

Why would that be odd? Bacteria will thrive in a range of conditions. There are millions upon millions of species and there are virtually no conditions known on this planet where at least some of them don't thrive.

 

[snusmumriken]

Why would that be odd? Bacteria will thrive in a range of conditions. There are millions upon millions of species and there are virtually no conditions known on this planet where at least some of them don't thrive.

Yes I know that. But why would they be in my darkroom? There is no hydrothermal vent or sulphur spring in there.

 

[Alex Benjamin]

Never happened with my TTB. Mine never lasts more than a few days, as I usually mix a new batch as soon as I have about 10-12 films I want to develop in it. I always use distilled water when mixing.

What I have found that needs a more than thorough wash is the 600ml plastic beeker I use for bath B. It does develop a black stain or residue when dried if not cleaned well (not just rinced). Ever since I noticed that, I've taken the habit of filling with water the empty bottles of both A and B until I make a new batch.

 

[Alex Benjamin]

I should add that I have two dedicated beekers for bath A and B, that I use for nothing else, in order to avoid cross-contamination, mostly with other chemicals. Again, I've started that after noticing a residue on the bath B beeker.

 

[snusmumriken]

Never happened with my TTB.

Never say never. It had never happened to me before!

I should add that I have two dedicated beekers for bath A and B, that I use for nothing else, in order to avoid cross-contamination, mostly with other chemicals.

Yes, so do I. Apart from developing tanks, all my bottles, trays, funnels, etc are dedicated to one chemical only.

I think I'll give my Bath B bottle the Ilford glassware cleaner treatment. I can't imagine there are bacteria able to tolerate sulphuric acid and potassium permanganate at the same time.

 

[koraks]

Yes I know that. But why would they be in my darkroom? There is no hydrothermal vent or sulphur spring in there.

Wait, you expected that there would be no bacteria in your darkroom...?

 

[Alex Benjamin]

I can't imagine there are bacteria able to tolerate sulphuric acid and potassium permanganate at the same time.

Just be careful not to create a new lifeform. Things are bad enough as it is.

 

[snusmumriken]

Wait, you expected that there would be no bacteria in your darkroom...?

You are talking to a biologist here. But you must admit, this is an uncommon occurrence?

 

[MattKing]

When I saw this thread's title, for some reason I thought of a movie from the Coen brothers .
A lot of the stuff we work with can provide a great environment for bacteria and other things that cause things to smell.
The same applies to cooks.

 

[Don_ih]

The worst smelling thing I had in my darkroom was one particular batch of Parodinal that smelled like a septic tank filled with rotten fish. Worked great, but it smelled truly awful. I didn't end up using all of it.

Odd thing about it: all materials used to make it had also been used to make the previous batch, which didn't cause me to gag.

 

[Alex Benjamin]

When I saw this thread's title, for some reason I thought of a movie from the Coen brothers

I thought of this exchange between Sherlock Holmes and Detective Gregory of Scotland Yard:

— Gregory: Is there any other point to which you would wish to draw my attention?
— Holmes: To the curious incident of the dog in the night-time.
— Gregory: The dog did nothing in the night-time.
— Holmes: That was the curious incident.

 

[koraks]

But you must admit, this is an uncommon occurrence?

Sure - uncommon, but not exceedingly unlikely.

 

[snusmumriken]

I thought of this exchange between Sherlock Holmes and Detective Gregory of Scotland Yard:

— Gregory: Is there any other point to which you would wish to draw my attention?
— Holmes: To the curious incident of the dog in the night-time.
— Gregory: The dog did nothing in the night-time.
— Holmes: That was the curious incident.

Exactly so. Of course in this case something did happen, but that turn of phrase appealed.

 

[Alan Johnson]

It may be possible for methylamine to be formed.

Metol, hydrolysis

It's not really known why old metol based developers don't last indefinitely. It might be because the metol reacts with OH ions from the water (hydrolysis) giving hydroquinone and methylamine as in the attachment.(I left out the sulfite for simplicity, they are likely further sulfonated from the...

www.photrio.com

However it did not happen in my experiment with anaerobic metol solution.
Air may be involved somehow. I have had it with BTTB part 2.

 

[grahamp]

I have had a BTTB sodium metaborate bath start to stink. It only happens with stock that has been used, and not always. Unused part B stock has always been fine.

 

[koraks]

I suspect exposure to a gelatin emulsion has something to do with it. Just a hunch though.