Ilford Fixer bottle blue stain.

[Peter_S]

Hi!
I just notice that the bottle with Ilford Rapid Fixer is stained dark blue inside. When you poor the liquid out it is still clear. I set the fixer up 6 weeks ago and used it for one tank only back then. Any idea what causes the blue stain, is it expired? I kept in an old fixer bottle, so it should be tight.
It smells a little like old egges, so I suspect something related to sulphur.

 

[Freakscene]

The egg smell is sulfur dioxide:
http://www.rangefinderforum.com/forums/showpost.php?p=1534538&postcount=5

The blue stain could be a thin layer of deposited metallic silver.

Fixer is still okay for film if the silver content is under 6 g/L, or roughly if the clearing time is less than twice the clearing time of fresh fixer. For paper 2 g/L is the limit for archival stability of the media.

Marty

 

[V-12]

Fixer keeps well if it hasn't been contaminated and the smell and low number of film's you've put through it suggest it is contamination, possibly from not using a stop bath or not rinsing the film well enough between the developer and fixing cycle.

V

 

[Freakscene]

Fixer keeps well if it hasn't been contaminated and the smell and low number of film's you've put through it suggest it is contamination, possibly from not using a stop bath or not rinsing the film well enough between the developer and fixing cycle.

Like most fixers, Ilford Fix is acidic. The reduction and sulfur precipitation can occur with age, irrespective of use. Thiosulfates are stable only in neutral or alkaline solutions, but not in acidic solutions.

It may be contaminated, but it need not be. Also remember that chemically speaking, the silver from previous use is a contaminant that catalyses reactions in thiosulfates.

Marty

 

[Peter_S]

Hi!
Thanks for the detailed information...made me look into my AP Chemistry book again for the first time in years 🙂
Anyhow - I checked the fixer and it cleared just like it should, so I reused it and all came out fine. That said, there was a substantial amount of dark crystals (silver sulphide?) at the bottom of the bottle and all, incl. stop bath, will go to the special garbage disposal asap. No idea what happened, I have never seen this before, even with the same fixer. Hopefully it was the last time.

Thaaanks!
Peter

 

[V-12]

Like most fixers, Ilford Fix is acidic. The reduction and sulfur precipitation can occur with age, irrespective of use. Thiosulfates are stable only in neutral or alkaline solutions, but not in acidic solutions.

It may be contaminated, but it need not be. Also remember that chemically speaking, the silver from previous use is a contaminant that catalyses reactions in thiosulfates.

Marty

It's all very well sitting on the fence and saying it could be this-or-that, but I'm in the proactive 'better safe than sorry' camp and would treat it as contamination whatever the cause and not risk it.

V