Discoloration in Ilford Rapid fixer

[Joao]

Very basic question: I used to keep diluted Ilford Rapid fixer in plastic bottles, in the dark, without problems.
This time I kept it in a glass bottle with a metal lid/cap and after a couple of days its colour looked like tea, and a brownish deposit was present inside the walls of the bottle. No signs of corrosion on the metal (painted) lid (some minor spots of rust, not in direct contact with the fixer). What could have caused this ? I washed the bottle before I poured the fixer in, but maybe some contaminant residue persisted… Or was the metal lid responsible for it ???
The brownish discoloration was easily removed with a cylindrical bottle-washing brush. Photo of the bottle (the fixer was expected to look like the water in the small bottle…). Any ideas ??

 

[DownUnder]

A few tried-and-true tricks an old-timer in the darkroom taught me, many decades ago.

Cut a small strip of unexposed film and fix it for the usual time. If it clears, the fix is okay.

If it's good, then filter it. I use Melitta coffee filters in an old plastic filter.

Then use the filtered fixer asap.

 

[Freakscene]

Was the fixer used? White, off white or yellow precipitate in used or old fixer is amorphous sulfur from reduction of thiosulfate. Dark precipitate is usually antihalation dye, but that can only be there is the fixer was used.

Also see: Kodak T-Max 400 Fixing Query Your best criterion for film is 6 mg/l silver. Twice the clearing time is useful if you measured clearing time for fresh fixer, but most people don’t.

Marty

 

[Joao]

The fixer was used once - one roll of Eastman plus-X .The fixer was crystal clear when I poured it from the tank into the bottle. The discoloration was visible a couple of days later, and got worse in the following days. When I discarded it the fixer had a tea-like discoloration.
A new batch of fixer was prepared and another plus-X roll was fixed. The fixer now is in a plastic bottle and shows no discoloration so far.
And yes, I could have filtered it - I did not considered that option...
Thank you for your replies
Regards
Joao

 

[Freakscene]

The fixer was used once - one roll of Eastman plus-X .The fixer was crystal clear when I poured it from the tank into the bottle. The discoloration was visible a couple of days later, and got worse in the following days. When I discarded it the fixer had a tea-like discoloration.
A new batch of fixer was prepared and another plus-X roll was fixed. The fixer now is in a plastic bottle and shows no discoloration so far.
And yes, I could have filtered it - I did not considered that option...
Thank you for your replies
Regards
Joao

With movie film there are additional anti-static agents and lubricants in the antihalation layer behind the film base. When the products are dissolved they are clear, but they colour up when they precipitate. Fixer can hold way more silver in solution than you would ever get in it from normal photographic use.

Marty

 

[Joao]

Thank you Marty for the aditional information. I have some more rolls of -plus-X to use. I will see what happens.
Regards
Joao

 

[titrisol]

A few tried-and-true tricks an old-timer in the darkroom taught me, many decades ago.

Cut a small strip of unexposed film and fix it for the usual time. If it clears, the fix is okay.

If it's good, then filter it. I use Melitta coffee filters in an old plastic filter.

Then use the filtered fixer asap.

The undeveloped piece of film should clear in 1/4 to 1/3 of the fixing time.
Coffee filters are OK, but you might be getting coloidal sulfur dispersion by hte decomposition of thiosulfates.

I've found that as an amateur it is more effective to use the fixer one shot (one session)
It might seems expensive but its cheaper than losing rolls

 

[DownUnder]

I bought a shipload of fixer about ten years ago when a few Melbourne photo shops closed down/cut back on their stocks and discounted their darkroom chemistry. Ended up with ten bottles of liquid fix, which I keep stored at home in a temperature controlled area of our house.

Used it little by little over the years. Like titrisol, I tend to underuse my fix, one batch mixed for one session (usually several rolls of film to be processed in one lot), and then I dispose of it.

I think I still have one bottle of Agfa Universal fixer left. I must look for it and see to it that it gets used up.

Some of it smelled "odd" but when I did the film leader tests, it cleared everything okay. So I used it.

Yes, maybe my negatives will disappear in the next half century. Should I care? I no longer use film on my Asian travels, haven't for well over a decade. So yet more cat pictures sent to the universe...

 

[Freakscene]

I bought a shipload of fixer about ten years ago when a few Melbourne photo shops closed down and discounted all their darkroom chemistry. Ended up with about ten bottles of liquid fix, which I kept stored at home in a temperature controlled area of our house.

Used it little by little over the years. Like titrisol, I tend to underuse my fix, one batch mixed for one session (usually several rolls of film to be processed in one lot), and then dispose of it.

I think I still have one bottle of Agfa Universal fixer left. I must look for it and see to it that it gets used up.

Some of it smelled "odd" but when I did the film leader tests, it cleared everything okay. So I used it.

Yes, maybe my negatives will disappear in the next half century. Should I care? I no longer use film on my Asian travels, haven't for well over a decade. So yet more cat pictures sent to the universe...

The odd smell is sulfur dioxide: milky fixer

It still works.

Marty