Silver precipitating out of fixer

[Gary L. Quay]

I seem to be getting shiny flakes of what looks like silver floating around in my fixer. For the fixer I use for film, I use TF4, and the flakes are about 1/8", and for paper I use Clayton AFC Archival Fixer, and it takes the form of a black, granular residue on the bottom of the bottle or tray. I use distilled water, and (generally) a running water stop instead of a stop bath. I think it's odd. The folks at the camera store where I take my fixer have pointed out the residue or flakes, so I have to get this figured out before I can take some there again for recycling.

Any help is greatly appreciated.

Thanks!

--Gary

[Jim Noel]

I don't understand why the store will not take your fixer with the flakes in it. Recyclers simply remove and collect the silver from the fixer and sell it. If these are in fact silver, why wouldn't they want it?

[Gem Singer]

Filter out the silver precipitant with a coffee filter.

Re-use the fixer until it reaches it's capacity, then flush it down the drain.

Unless you are using a huge amount of fixer, no need to recycle it.

[Tom Monego]

Are you using an alum hardener in the fix? If you are this could be aluminum sulfate (?) precipitating out. This can happen with too much hardener being used. My photo chemistry doesn't get tested as much as it used to. Many years ago I used to work for Sprint Systems and knew all this stuff.

Tom

[Gem Singer]

Tom, the fixers that he is using are non-hardening fixers.

[Lachlan 717]

I've had the thing happen with Tefenal Superfix. Just got a tea strainer from the kitchen and got on with it. Didn't seem to have any effect; no chunks left on the film!!

As Gem suggests, filter it and keep on using it!

[IanG]

A tea strainers not enough to do much at all, use a coffee filter.

Ian

[IanMazursky]

Filter out the silver precipitant with a coffee filter.
Re-use the fixer until it reaches it's capacity, then flush it down the drain.
Unless you are using a huge amount of fixer, no need to recycle it.

I really wouldn't recommend dumping silver rich fixer down the drain. Its a heavy metal and not good for the sewer system and the environment.
If you have a septic tank and leach field then it could be a disaster. It could contaminate your tank, ground and possibly ground water
The easiest thing to do is to put a bunch of pieces of steal wool in a 5 gallon bucket. The best kind is the fine steel wool, they look like hot pockets.
Home depot has it for under $10 a pack. I buy a few packs every quarter and dump them into my system.

Pour all of your fixer in the bucket and the silver will plate onto the steel and remember to stir occasionally.
I forget the actual chemical process but silver sludge will form and end up at the bottom of the bucket. It looks like a grayish black sludge.
After a few weeks or months depending on usage, you can draw off and dump the fixer from the top with a lot water.
Remember not to let the sludge or the wool go down the drain. Its slightly valuable and not good for the environment.
You can keep adding steel wool and fixer until the sludge layer is thick enough to collect.
You can try to have it refined or at least dispose of it properly. Some recycling centers may take it or a silver refinery. The phone book or google can help with that.

This is basically the same as buying one of those silver recovery cartridges. In those, the steel wool is wrapped around a casing and the fixer flows through and around it.
They probably have a higher silver recovery yield and are easier to refine but they are a bit expensive.
The steel wool bucket approach will probably not remove 100% of the silver from the fixer but you are reducing it a lot.
Enough that i feel comfortable dumping the fixer after a month in the bucket.

If those are silver flakes that came out of solution, you may be able to strain them out and use some fresh fixer to bring them back into solution.
Then dump it into a steel wool silver recovery bucket mentioned above.

Hope that helps.

[Lachlan 717]

A tea strainers not enough to do much at all, use a coffee filter.

Ian

You must use a different model to me, Ian. The one I use is fine. The solids are around 3mm in length; easily large enough for a poor-quality strainer to catch. In fact, the whole reason I used a strainer is because the flakes looked like tealeaves. So, please don't tell me what works for me and what doesn't.

[IanMazursky]

I just thought of this, You can also use a fish net with a coffee filter placed in the net.
Its like catching fish in a pet store tank before you bring them home :D

But seriously, i am using coffee filters to clean my fix after using it for Pyro. It works really well.
Ive seen different type of tea strainers, some have a really fine mesh. Some are even gold plated or so they say.
They may work just fine as long as they are stainless steel. Ive had a few cheap ones that came with my tea pots.
They rusted out within a year then we had to buy better ones. Those tea pots weren't cheap either, just the strainer :(

[Gary L. Quay]

I don't understand why the store will not take your fixer with the flakes in it. Recyclers simply remove and collect the silver from the fixer and sell it. If these are in fact silver, why wouldn't they want it?

The folks at the camera store worry about contamination of fixer by developer. They say that it ruins the batch. The owner seemed to think that silver never precipitated out of the fixer by itself, and they were worried that the sediment may be some other form of contamination. My questions should have been: Can silver precipitate out of the fixer on its own? What can I tell the guy at the camera store to ease his concerns?

Thanks for the responses.

--Gary

[Gem Singer]

Gary,

Are you using a Pyro developer and a water stop bath?

[nolindan]

Sounds like you are carrying over active developer into the fix. Try using a proper stop bath or use multiple rinses after the developer.

[Brian Ellis]

You will extend the life of your fixer - and might conceivably even eliminate the problem you're having - if you use a stop bath rather than water. Considering the advantages of stop bath over water, and considering how little it costs and how long it lasts, I've never understood why anyone uses water unless they don't like the smell. But even that can be dealt with - I used a stop bath that smelled like vanilla extract - very pleasant.

[Gem Singer]

Brian, you're correct, there are citric and boric acid stop baths that have a much more pleasant odor compared to acetic acid. However, the use of an acid stop bath and an acid fixer tends to reduce the useful staining effect of a pyro developer.

Also, keeping the chemical processing of film and fiber base paper at a neutral or alkaline ph makes it easier and faster to wash out the fixer.

(see: Anchell and Troop, "The Film Developing Cookbook").

[IanG]

You must use a different model to me, Ian. The one I use is fine. The solids are around 3mm in length; easily large enough for a poor-quality strainer to catch. In fact, the whole reason I used a strainer is because the flakes looked like tealeaves. So, please don't tell me what works for me and what doesn't.

Lachlan, a tea strainer is usually totally inadequate or I wouldn't have made the comment.

The OP asked about silver precipitating out, this is usually a finer colloidal silver sludge that even the finest tea strainer won't help remove.

What you're describing is metallic silver that's plated out on the side of a storage bottle, then flaked off, so yes that would easily be filtered out with most tea strainers.

So I WILL tell people what works better, that's why people share information on these Forums.

Ian

[Tom Monego]

You can add a drop of Vanilla extract to you stop bath, will drop the smell. Stop baths do help, if you use water you are not completely arresting development, a small amount of development will take place. The only problem with stop baths is if the developer has sodium or potassium carbonate as the accelerator as this can possibly cause air bells in the emulsion of the film, cutting back on the acid concentration will help with this. Stop will help keep your fixer clean, always mix to the directions on the bottle, the one glug method, as I was taught generally gives to high a concentration of acid. I'm sure there are directions out there for white vinegar, glacial acid acid etc.

Tom

[Bob McCarthy]

You will extend the life of your fixer - and might conceivably even eliminate the problem you're having - if you use a stop bath rather than water. Considering the advantages of stop bath over water, and considering how little it costs and how long it lasts, I've never understood why anyone uses water unless they don't like the smell. But even that can be dealt with - I used a stop bath that smelled like vanilla extract - very pleasant.

Some of us are using alkaline fixers. An acid stop is a no-no.

Alkaline fixers sure wash out easily.

However the fixer smell is less than desireable.

bob

[IanG]

Some of us are using alkaline fixers. An acid stop is a no-no.

bob

I think Ron Mowrey (ex Kodak) who designed some of the Alkaline fixers actually recommends an acid stop bath with them, they are well buffered.

Double checked he posted only yesterday that an Acid stop bath can be used with an Alkaline fixer.

Ian

[Gary L. Quay]

Gary,

Are you using a Pyro developer and a water stop bath?

I occasionally use Pyro, but I always use a water stop for film and FB paper. I had read that a water stop greatly decreases the amount of water needed to wash film and paper. I use clean working fixers (TF4, Clayton AFC) to make washing shorter, the use of an acid stop bath would seem to defeat the purpose. Photographers' Formulary cautions not to use a stop bath with TF4. Although, I possibly could get away with it for film, because I could add a rinse between the stop and the fixer, but FB paper absorbs lots of chemicals. Even if the guy from Kodak says that they're well buffered, there would be a lot of contamination with fiber paper.

Thanks for the help so far!

--Gary

[Kirk Keyes]

I had read that a water stop greatly decreases the amount of water needed to wash film and paper.

Gary - that's info is wrong. What was the source?

A water rinse actually takes more water than a stop as the washing for the fixer will proceed at the same rate regardless of whether a stop was used or not.

Stop baths can actually help remove some developing agents. But mostly they stop development quickly so it can't continue in water washes or even alkaline fixers.

[Gary L. Quay]

Gary - that's info is wrong. What was the source?

A water rinse actually takes more water than a stop as the washing for the fixer will proceed at the same rate regardless of whether a stop was used or not.

Stop baths can actually help remove some developing agents. But mostly they stop development quickly so it can't continue in water washes or even alkaline fixers.

I've been hearing it for years from various sources. When using an alkaline fixer, as opposed to an acid fixer, it's important to maintain alkalinity throughout the processing. Photographers' Formulary even suggests a water stop. An acid stop, from what I've heard, will change the ph, especially of FB prints, and make them more difficult to wash. More water is used in the stop, but it's more than made up for in the final wash. At least, this is what I've heard. I'd be happy to return to a stop bath if this isn't true.

--Gary

[Kirk Keyes]

Bill Troop, inventor of TF-4 alkaline developer has the notion that an "all" alkaline process is more elegant than one that goes from alkaline to acid to alkaline again and so he promoted the "all alkaline" processing technique.

Having that acid step in there is not a big deal, and when you put the film into the alkaline fixer, the pH of the paper goes alkaline - it forgets about that acid step and goes to whatever pH the fix is.

Ron Mowrey, an ex-Kodak film engineer and inventor of the Formulary's "Superfix" and TF-5 with Bill Troop alkaline fixers, has said that Stop CAN be used with TF-4. TF-4 is pretty well buffered - that's some of what all that sludge in the bottle is before you mix it, and it can handle the use of a stop bath.

[Gary L. Quay]

Okay. Thanks!

--Gary