Filtering fix for film development

Sim2 · Feb 20, 2010

Hallo,

This may be a bit of an odd question, but here we go....

When a film is fixed I believe that silver particles from the film go into solution in the fix. If that fix is reused for another film i.e. still fresh and active etc, what chance is there of the silver particles affecting the next film i.e. by srcatching, marking or getting stuck on the film?

I assume that any particles that exist should be washed out during an effective wash but am thinking about the scratching possibilities of any particles.

If this is correct, should used fix be filtered before being reused and if so what filtration level will filter out silver particles e.g. 20 microns, 10 microns or 1 micron etc?

Perhaps a bit theorectical but thought I would ask anyway!

Cheers for any feedback,

Sim2.

dancqu · Feb 20, 2010

A Misconception

Sim2 said:
When a film is fixed I believe that silver particles
from the film go into solution in the fix.

There are no particles of silver. The silver is chemically
bound atom by atom to the fixers thiosulfate. Dan

AgX · Feb 21, 2010

Sim2 said:
When a film is fixed I believe that silver particles from the film go into solution in the fix.

You already gave the answer yourself: solution

Ian Grant · Feb 21, 2010

dancqu said:
There are no particles of silver. The silver is chemically
bound atom by atom to the fixers thiosulfate. Dan

Actually there can be particles of silver, particularly if you use a plastic container, they plate out onto the sides but the bond is so weak some go into suspension.

They can be filtered out as soon as you put the fixer back more forms

Ian

Sim2 · Feb 21, 2010

Ops, hit the reply button too soon!

Sim2 · Feb 21, 2010

Aaarrgh! More confused now. :confused:

So, it seems that there can be silver particles in used fix, either in solution which to me means floating about in rather than dissolved into the liquid or clinging to a plastic container waiting to rush out all over a new film!

Ok, so silver particles seem to be in used fixer.
My question now will be:
Can these particles affect a new film being fixed, either by scratching the neg or adhereing to the neg like a dust spot?
If the fix has particles in it from the storage medium, is there an advantage in filtering it as it is poured into the dev tank?
After the fix is decanted from the film should any particles left behind be swept out by an effective wash?

Or is this all just theoretical waffle?
Just trying to really nail down the processing procedures for optimum results.

Sim2.

Ian Grant · Feb 21, 2010

Generally the silver does no damage, it can't scratch the film, and most drops to the bottom of the bottle anyway so don't shake before use. These particles of silver are in suspension, they are extremely fine and yes a good wash should remove them.

Ian

Sim2 · Feb 21, 2010

Ian Grant said:
Generally the silver does no damage, it can't scratch the film, and most drops to the bottom of the bottle anyway so don't shake before use. These particles of silver are in suspension, they are extremely fine and yes a good wash should remove them.

Ian

Thanks very much for this reply.
For some odd reason I have agitated the fix bottle before using - this shall cease forthwith!

At least one thing can be ticked off my *processing worries* list. Now, what was next.....

Cheers,
Sim2.

Anscojohn · Feb 21, 2010

Sim2 said:
Thanks very much for this reply.
For some odd reason I have agitated the fix bottle before using - this shall cease forthwith!

At least one thing can be ticked off my *processing worries* list. Now, what was next.....

Cheers,
Sim2.

*****
Well, Sim2, in ye olden dayz we were told to shake the bottle before use. By the same token, I do not recall ever seeing or hearing of problems such as you posit coming from silver in the fixer.

mooseontheloose · Feb 21, 2010

Can these particles affect a new film being fixed, either by scratching the neg or adhereing to the neg like a dust spot?

I've had this problem occur (spots on the negative from silver particles), and, although I could be wrong, I've always assumed it to be from reusing the fix. I now use everything one shot (developer one shot, no stop, fix one shot) and haven't had any problems like that since.

Ian Grant · Feb 21, 2010

Having had a commercial darkroom (3 photographers sharing) where we replenished the fixer for months on end I can honestly say re-use normally causes no issues, but you should not deliberately stir up the sediment at the bottom.

Personally I filter my fixer every so often to avoid these issues, but before rather than after use.

Ian

Sim2 · Feb 21, 2010

Seems to me that this may be summarised as follows:

Silver particles do exist in pre-used fixer.

Ultimate workflow irrespective of cost
Use dev, stop and fix as one-shot chemicals, disposing after use.

Pragmatic workflow
Reuse fix in film develpment, but don't shake the storage container before use, occasionaly filter the fix into a glass recepticle before fixing a film, wash film adequately.

Although I can see an advantage of the ultimate workflow, for cost considerations the pragmatic workflow is probably the one I shall follow.

Thanks for all the input.

AgX · Feb 21, 2010

Sim2

With "in solution" I meant "dissolved". The silver is ionic and no longer visible. This is the typical state of silver in a fixer that is ok.

Ian means solid, metallic silver that floats for a while as miniscule particles, before they finally sink down. Small amounts of silver have precipitated before on the reels eg. and were washed off so to say.

Filtering fix for film development

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