Silver precipitating out of fixer

[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