Filter chemicals

[philipus]

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Has anyone tried to filter developing chemicals, esp fixer, using reusable coffee filters, such as this one?

 

http://amzn.to/2c6Cql7

 

I've only used ordinary filters and a funnel but the paper tends to break after a while so I'm looking for alternatives.

 

Br

Philip

[earleygallery]

I've never had to. Why do you need to filter them?

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[pico]

There should be no reason for filtration, but if you must then paper coffee filters in the correct basket funnel suffices.

[chris_livsey]

Flute the paper, google will show you if that sounds odd. Coffee filter paper works for me, when I need, it my lab paper is too small and the strength is equivalent.

[philipus]

Thanks James. The thing is I tend to forget to mix new fixer and only discover that the fixer is full of little specs when I scan a roll. 

 

I've never had to. Why do you need to filter them?

 
Thanks Pico. Perhaps I've used the wrong type of funnel - by "correct basket funnel", do you mean the same type that is used for coffee making, say a size 4?
 

There should be no reason for filtration, but if you must then paper coffee filters in the correct basket funnel suffices.

 
Thanks Chris. What do you mean by "flute" the paper?
 

Flute the paper, google will show you if that sounds odd. Coffee filter paper works for me, when I need, it my lab paper is too small and the strength is equivalent.

[chris_livsey]

 
Thanks Chris. What do you mean by "flute" the paper?

 

 

It increases surface area available to filter, speeds it up so the paper is loosing wet strength for less time reducing "breakage", that is usually due to overloading, resist the temptation to keep topping it up, the flow reduces as the particulates clog the paper, more efficient to use a new sheet than increase the weight forcing the liquid through by topping up which "breaks" the paper. 

Standard lab practice if using gravity filter, alternative is not easy at home, vacuum filtration.

[honcho]

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Has anyone tried to filter developing chemicals, esp fixer, using reusable coffee filters, such as this one?

 

 

 

I don't use paper coffee filters, phillipus, but I do use an ancient but still very serviceable Paterson filter funnel (not sure if they are still available). 

 

I've always filtered developers that are mixed from powders and both fix and stop bath solutions as they are poured into graduates through the filter funnel before being brought to the correct working temperature. 

Edited August 25, 2016 by honcho

[fotohuis]

You can use a stainless steel grid like Paterson. A Coffee filter is already much finer but it works too. Normally you should not need to use a filter unless you are making your own chemicals from scratch. To get it easier dissolve you can use an ultrasonic bath too, apart from a higher dissolving temperature for most chemicals (50C).

[Maarten]

A quick and dirty filtration can be done using a small piece of cotton-wool in a glass funnel.

I agree that a filtration over paper is usually not needed.

A filtration over cotton-wool gives me a dust and particle free solution of fixer or developer and takes just a few minutes.

[philipus]

Thanks Maarten. This is an ingenious way, which I will try. Do you use any cotton wool or must it be one that doesn't release parts/threads/bits into the solution (if so, which kind)?

 

br

Philip

 

 

A quick and dirty filtration can be done using a small piece of cotton-wool in a glass funnel.
I agree that a filtration over paper is usually not needed.
A filtration over cotton-wool gives me a dust and particle free solution of fixer or developer and takes just a few minutes.

[Maarten]

I use a glass funnel with just a little piece of cotton-wool, smaller than a dice when dry.

I wett the cotton with a little water so it loses all its fibres. Then I filter the developer or fixer.

You have to make sure there is no pressure build-up under the funnel, otherwise the cotton-wool is pushed up and your filtration fails.

If needed I can pm you the address where I could buy a small glass funnel. Plastic funnels are a bit too big for this method.

[philipus]

Thank you Maarten. This is very helpful. I'll try it with my funnel. I bought it at Blokker so it is of plastic but it is quite wide actually. 

 

I use a glass funnel with just a little piece of cotton-wool, smaller than a dice when dry.
I wett the cotton with a little water so it loses all its fibres. Then I filter the developer or fixer.
You have to make sure there is no pressure build-up under the funnel, otherwise the cotton-wool is pushed up and your filtration fails.
If needed I can pm you the address where I could buy a small glass funnel. Plastic funnels are a bit too big for this method.

[Martin B]

I once filtered my freshly made Kodak fixer solution because it contained some insoluble white particles which did not dissolve in the recommended amount of water. I used a coffee filter (Melitta #4), and I got rid of most of the bigger particles. Some smaller ones still leaked through the filter pores, but I didn't see this as an issue.

Edited September 21, 2016 by Martin B

[tobey bilek]

It is not crud in the developer, it is crud in the fix.  

 

After time,  silver precipitates out from the USED fix as small grey particles that settle to the bottom. If you use a glass bottle, you can see them.   They then adhere to the emulsion side of the next film and will not wash off even with direct stream of water.

 

Some are large, some are small.  Almost none will be trapped by a coffee filter.  

 

A lab grade filter paper might work.    I have never been able to figure how all the old labs solved this problem.  Perhaps a centrifuge.  Perhaps they let it settle and pour off the top. Perhaps they use steel wool which is a base for silver plate, a recovery method for recycling.  

 

I solved the issue by not reusing fix except for print test strips. 

 

Do this and get water and HEPA air filters and a clean darkroom for drying and all the problems will go away.  40 years of problems gone away.  

[NB23]

Reusing fixer is obviously a standard out there. Fixer is expensive enough!

 

I've never had trouble washing my films and I reuse the fixer to an acceotable degree well within its working range.

 

Hypo clearing agent might help. Do you use it?

[fotohuis]

Fixer for film you can re-use till it is saturated (approx. 2g/liter Ag+ ions, for a test with test strips of test solution with KI). HCA for film is a waste of money.

An effective film fixer 1+4 you can use till approx. 6 months. After it you can have precipitation. But also the fix concentrate has a lifespan of several years, at the end it will fall apart in Sulfur, which you can smell.

[NB23]

Fixer for film you can re-use till it is saturated (approx. 2g/liter Ag+ ions, for a test with test strips of test solution with KI). HCA for film is a waste of money.

An effective film fixer 1+4 you can use till approx. 6 months. After it you can have precipitation. But also the fix concentrate has a lifespan of several years, at the end it will fall apart in Sulfur, which you can smell.

Yes I agree, HCA is a waste of money on film. However, if the precipitate sticks to film and wont wash away (as discussed here), this might be a situation where HCA might be valuable.