White precipitate in my fixer?

[frank]

Hi guys. Please excuse the chemistry-newbie question, it's just not my thing.

What's the white precipitate in my fixer? It's been sitting a while, but it cleared a clip of film quickly enough and my fix testing drops do not cause a precipitate.

So can you say what it is and if it's a concern even though the film clears?

Thanks.

 

[snikulin]

It's sulfur me thinks (it's pale yellowish actually).
At this point I usually discard the solution and make a new gallon.
Small sulfur particles can stick to the emulsion.

 

[frank]

Thanks. I filtered it.

 

[Gerald C Koch]

The problem is that once it starts it continues to throw down sulfur. Just discard it and get fresh. Should any particles stick to the film emulsion they are impossible to remove without damaging the film.

 

[Anon Ymous]

I've seen rapid fixer precipitating sulfur, but it wasn't a white precipitate. It was yellow crystals that covered the walls of the bottle. The fixer still cleared film reasonably fast, but I wouldn't dare using it. In one case it was an old unopened bottle, stored in probably bad conditions.

 

[kiemchacsu]

I got the same issue with kodak fixer. I discovered that heating the liquid will help to dissolve the precipitate.
Still not so sure if it would affect the fixing process since films still get clear.

 

[frank]

This is Kodak fixer mixed from a packet, and it's definitely white powder, not yellowish, with no odor. Warming to assist re-dissolving makes sense. Ambiant temperature in that room is falling these days with the change of seasons. My house furnace temp is set quite low for economy and we wear slippers and sweaters during the winter.

 

[MattKing]

This is Kodak fixer mixed from a packet, and it's definitely white powder, not yellowish, with no odor. Warming to assist re-dissolving makes sense. Ambiant temperature in that room is falling these days with the change of seasons. My house furnace temp is set quite low for economy and we wear slippers and sweaters during the winter.

Do you use this fixer for prints as well? If so, reserve this bottle for that purpose. And continue to do film clearing tests on the film strength portion of it until you have used it up.

 

[frank]

Sounds like a good plan, thanks Matt.

 

[Gerald C Koch]

For the record very finely divided sulfur appears white. It is only when it is present in larger sized grains or crystals that it appears yellow.

 

[Ken Nadvornick]

If the sulfur precipitate sticks to the insides of the bottle it can sometimes be hard to remove it all. Especially if the bottle is narrow-mouthed and one doesn't have a narrow bottle brush.

In this case one thing that might help is to pour a small amount of xylene or toluene (sold as paint thinners) into the bottle, cap it, and let it sit for a few days at room temperature. These are very mild sulfur solvents and will help remove the remaining precipitate film from the insides of the bottles.

And before anyone says this won't work, I just finished successfully doing it for a pair of Kodak F-5 fixer bottles that precipitated. I first removed as much precipitate as I could mechanically, then poured in small amount of xylene, capped them, and let them sit for several days at room temperature with only an occasional shaking.

Worked like a charm. The brown glass Boston Round bottles are now as crystal clear as they were when brand new. It also removed the coating from the poly seal cones inside the caps.

Ken

 

[Gerald C Koch]

Another trick to cleaning bottles is to put some scouring powder like Bon Ami in the bottle with a couple of tablespoons of rice or beans and a bit of water. Then shake the bottle until clean. The rice or beans helps rub the Bon Ami on the bottle surfaces.